diff --git a/packages/bigframes/bigframes/core/bytecode.py b/packages/bigframes/bigframes/core/bytecode.py
new file mode 100644
index 000000000000..ba5071604da2
--- /dev/null
+++ b/packages/bigframes/bigframes/core/bytecode.py
@@ -0,0 +1,264 @@
+# Copyright 2025 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import dis
+import operator
+from types import ModuleType
+from typing import Callable, Optional
+
+import bigframes.core.py_expressions as py_exprs
+from bigframes.core import expression
+
+
+class NullMarker:
+    pass
+
+
+_BINARY_OP_MAP = {
+    "+": operator.add,
+    "-": operator.sub,
+    "*": operator.mul,
+    "/": operator.truediv,
+    "//": operator.floordiv,
+    "%": operator.mod,
+    "**": operator.pow,
+}
+
+_COMPARE_OP_MAP = {
+    "==": operator.eq,
+    "!=": operator.ne,
+    "<": operator.lt,
+    "<=": operator.le,
+    ">": operator.gt,
+    ">=": operator.ge,
+}
+
+_OLD_BINARY_OP_MAP = {
+    "BINARY_ADD": operator.add,
+    "INPLACE_ADD": operator.add,
+    "BINARY_SUBTRACT": operator.sub,
+    "INPLACE_SUBTRACT": operator.sub,
+    "BINARY_MULTIPLY": operator.mul,
+    "INPLACE_MULTIPLY": operator.mul,
+    "BINARY_TRUE_DIVIDE": operator.truediv,
+    "INPLACE_TRUE_DIVIDE": operator.truediv,
+    "BINARY_FLOOR_DIVIDE": operator.floordiv,
+    "INPLACE_FLOOR_DIVIDE": operator.floordiv,
+    "BINARY_MODULO": operator.mod,
+    "INPLACE_MODULO": operator.mod,
+    "BINARY_POWER": operator.pow,
+    "INPLACE_POWER": operator.pow,
+}
+
+
+def _compile_bytecode_to_py_expr(func: Callable) -> Optional[expression.Expression]:
+    try:
+        instructions = list(dis.get_instructions(func))
+    except Exception:
+        return None
+
+    stack = []
+    globals_dict = func.__globals__
+    import builtins
+
+    builtins_dict = builtins.__dict__
+
+    closure_dict = {}
+    if func.__closure__:
+        free_vars = func.__code__.co_freevars
+        for var, cell in zip(free_vars, func.__closure__):
+            try:
+                closure_dict[var] = cell.cell_contents
+            except ValueError:
+                pass
+
+    for inst in instructions:
+        opname = inst.opname
+
+        if opname == "RESUME":
+            continue
+
+        elif opname == "LOAD_FAST_LOAD_FAST":
+            var1, var2 = inst.argval
+            stack.append(expression.UnboundVariableExpression(var1))
+            stack.append(expression.UnboundVariableExpression(var2))
+
+        elif opname.startswith("LOAD_FAST"):
+            stack.append(expression.UnboundVariableExpression(inst.argval))
+
+        elif opname in ("LOAD_CONST", "LOAD_SMALL_INT"):
+            stack.append(py_exprs.PyObject(inst.argval))
+
+        elif opname == "LOAD_GLOBAL":
+            name = inst.argval
+            found = False
+            val = None
+            if name in closure_dict:
+                val = closure_dict[name]
+                found = True
+            elif name in globals_dict:
+                val = globals_dict[name]
+                found = True
+            elif name in builtins_dict:
+                val = builtins_dict[name]
+                found = True
+
+            if found:
+                if isinstance(val, ModuleType):
+                    stack.append(py_exprs.Module(val))
+                else:
+                    stack.append(py_exprs.PyObject(val))
+            else:
+                stack.append(expression.UnboundVariableExpression(name))
+
+        elif opname in ("LOAD_ATTR", "LOAD_METHOD"):
+            if not stack:
+                return None
+            target = stack.pop()
+            stack.append(py_exprs.GetAttr(target, inst.argval))
+            if opname == "LOAD_METHOD":
+                if isinstance(target, py_exprs.Module):
+                    stack.append(NullMarker)
+                else:
+                    stack.append(target)
+
+        elif opname == "PUSH_NULL":
+            stack.append(NullMarker)
+
+        elif opname == "BINARY_OP":
+            if len(stack) < 2:
+                return None
+            right = stack.pop()
+            left = stack.pop()
+            op_symbol = inst.argrepr
+            if not op_symbol and isinstance(inst.argval, str):
+                op_symbol = inst.argval
+            if op_symbol and op_symbol.endswith("="):
+                op_symbol = op_symbol[:-1]
+
+            if op_symbol not in _BINARY_OP_MAP:
+                return None
+            stack.append(
+                py_exprs.Call(
+                    py_exprs.PyObject(_BINARY_OP_MAP[op_symbol]), (left, right)
+                )
+            )
+
+        # Support older Python versions compatibility
+        elif opname in _OLD_BINARY_OP_MAP:
+            if len(stack) < 2:
+                return None
+            right = stack.pop()
+            left = stack.pop()
+            stack.append(
+                py_exprs.Call(
+                    py_exprs.PyObject(_OLD_BINARY_OP_MAP[opname]), (left, right)
+                )
+            )
+
+        elif opname == "COMPARE_OP":
+            if len(stack) < 2:
+                return None
+            right = stack.pop()
+            left = stack.pop()
+            op_symbol = inst.argval
+            if op_symbol not in _COMPARE_OP_MAP:
+                return None
+            stack.append(
+                py_exprs.Call(
+                    py_exprs.PyObject(_COMPARE_OP_MAP[op_symbol]), (left, right)
+                )
+            )
+
+        elif opname in ("UNARY_NEGATIVE", "UNARY_INVERT"):
+            if not stack:
+                return None
+            target = stack.pop()
+            stack.append(
+                py_exprs.Call(
+                    py_exprs.PyObject(
+                        operator.neg if opname == "UNARY_NEGATIVE" else operator.invert
+                    ),
+                    (target,),
+                )
+            )
+
+        elif opname == "UNARY_POSITIVE":
+            if not stack:
+                return None
+            target = stack.pop()
+            stack.append(py_exprs.Call(py_exprs.PyObject(operator.pos), (target,)))
+
+        elif opname == "CALL_INTRINSIC_1":
+            if inst.argrepr == "INTRINSIC_UNARY_POSITIVE":
+                if not stack:
+                    return None
+                target = stack.pop()
+                stack.append(py_exprs.Call(py_exprs.PyObject(operator.pos), (target,)))
+            else:
+                return None
+
+        elif opname in ("CALL", "CALL_FUNCTION", "CALL_METHOD"):
+            num_args = inst.arg
+            if len(stack) < num_args:
+                return None
+            args = [stack.pop() for _ in range(num_args)][::-1]
+            if stack and stack[-1] is NullMarker:
+                stack.pop()
+            elif (
+                stack
+                and stack[-1] is not NullMarker
+                and isinstance(stack[-1], expression.Expression)
+            ):
+                self_arg = stack.pop()
+                args = [self_arg] + args
+            if not stack:
+                return None
+            callable_expr = stack.pop()
+            stack.append(py_exprs.Call(callable_expr, tuple(args)))
+
+        elif opname == "RETURN_VALUE":
+            if not stack:
+                return None
+            return stack[-1]
+
+        elif opname in ("STORE_FAST", "POP_TOP"):
+            if stack:
+                stack.pop()
+
+        else:
+            return None
+
+    return None
+
+
+def dis_to_expr(
+    func: Callable, unpack_mode: bool = False
+) -> Optional[expression.Expression]:
+    """
+    Try to convert a python function to a BigQuery expression.
+
+    Unpack mode is whether SQL columns are addressed as attributes of a single
+    python argument (e.g. row.col1), or as separate arguments (e.g. col1).
+
+    This is "best effort" - if the function contains operations that cannot
+    be converted to BigQuery expressions, it will return None.
+    """
+    try:
+        py_expr = _compile_bytecode_to_py_expr(func)
+        if py_expr is None:
+            return None
+        return py_exprs.resolve_py_exprs(py_expr, unpack_mode=unpack_mode)
+    except Exception:
+        return None
diff --git a/packages/bigframes/bigframes/core/py_expressions.py b/packages/bigframes/bigframes/core/py_expressions.py
new file mode 100644
index 000000000000..be26255534a9
--- /dev/null
+++ b/packages/bigframes/bigframes/core/py_expressions.py
@@ -0,0 +1,358 @@
+# Copyright 2023 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from __future__ import annotations
+
+import dataclasses
+import itertools
+from types import ModuleType
+from typing import Callable, Hashable, Mapping, Tuple
+
+import bigframes.operations.python_op_maps as python_op_maps
+from bigframes import dtypes
+from bigframes.core import identifiers
+from bigframes.core.expression import (
+    Expression,
+    OpExpression,
+    UnboundVariableExpression,
+    const,
+)
+from bigframes.operations import NUMPY_TO_BINOP, NUMPY_TO_OP, generic_ops, numeric_ops
+
+_CALLABLE_TO_OP = {
+    **NUMPY_TO_OP,
+    **NUMPY_TO_BINOP,
+}
+
+_BUILTIN_CALLABLES = {
+    str: generic_ops.AsTypeOp(dtypes.STRING_DTYPE),
+    abs: numeric_ops.abs_op,
+}
+
+
+@dataclasses.dataclass(frozen=True)
+class GetAttr(Expression):
+    input: Expression
+    attr: str
+
+    @property
+    def column_references(
+        self,
+    ) -> Tuple[identifiers.ColumnId, ...]:
+        return self.input.column_references
+
+    @property
+    def free_variables(self) -> set[str]:
+        return self.input.free_variables
+
+    @property
+    def is_const(self) -> bool:
+        return False
+
+    @property
+    def children(self):
+        return (self.input,)
+
+    @property
+    def nullable(self) -> bool:
+        return True
+
+    @property
+    def is_resolved(self) -> bool:
+        return False
+
+    @property
+    def output_type(self) -> dtypes.ExpressionType:
+        raise ValueError(f"Type of expression {self} has not been fixed.")
+
+    @property
+    def is_bijective(self) -> bool:
+        # TODO: Mark individual functions as bijective?
+        return False
+
+    @property
+    def deterministic(self) -> bool:
+        return True
+
+    def transform_children(self, t: Callable[[Expression], Expression]) -> Expression:
+        new_input = t(self.input)
+        if new_input != self.input:
+            return dataclasses.replace(self, input=new_input)
+        return self
+
+    def bind_variables(
+        self, bindings: Mapping[str, Expression], allow_partial_bindings: bool = False
+    ) -> GetAttr:
+        return GetAttr(
+            self.input.bind_variables(
+                bindings, allow_partial_bindings=allow_partial_bindings
+            ),
+            self.attr,
+        )
+
+    def bind_refs(
+        self,
+        bindings: Mapping[identifiers.ColumnId, Expression],
+        allow_partial_bindings: bool = False,
+    ) -> GetAttr:
+        return GetAttr(
+            self.input.bind_refs(
+                bindings, allow_partial_bindings=allow_partial_bindings
+            ),
+            self.attr,
+        )
+
+
+@dataclasses.dataclass(frozen=True)
+class Module(Expression):
+    """An expression representing a module reference."""
+
+    module: ModuleType
+
+    @property
+    def is_const(self) -> bool:
+        return True
+
+    @property
+    def column_references(self) -> Tuple[identifiers.ColumnId, ...]:
+        return ()
+
+    @property
+    def nullable(self) -> bool:
+        return True  # type: ignore
+
+    @property
+    def is_resolved(self) -> bool:
+        return False
+
+    @property
+    def output_type(self) -> dtypes.ExpressionType:
+        raise ValueError("Module expression does not have a type.")
+
+    def bind_variables(
+        self, bindings: Mapping[str, Expression], allow_partial_bindings: bool = False
+    ) -> Expression:
+        return self
+
+    def bind_refs(
+        self,
+        bindings: Mapping[identifiers.ColumnId, Expression],
+        allow_partial_bindings: bool = False,
+    ) -> Module:
+        return self
+
+    @property
+    def is_bijective(self) -> bool:
+        # () <-> value
+        return True
+
+    def transform_children(self, t: Callable[[Expression], Expression]) -> Expression:
+        return self
+
+
+@dataclasses.dataclass(frozen=True)
+class PyObject(Expression):
+    """An expression representing a module reference."""
+
+    value: Hashable
+
+    @property
+    def is_const(self) -> bool:
+        return True
+
+    @property
+    def column_references(self) -> Tuple[identifiers.ColumnId, ...]:
+        return ()
+
+    @property
+    def nullable(self) -> bool:
+        return True  # type: ignore
+
+    @property
+    def is_resolved(self) -> bool:
+        return False
+
+    @property
+    def output_type(self) -> dtypes.ExpressionType:
+        raise ValueError("PyObject expression does not have a type.")
+
+    def bind_variables(
+        self, bindings: Mapping[str, Expression], allow_partial_bindings: bool = False
+    ) -> Expression:
+        return self
+
+    def bind_refs(
+        self,
+        bindings: Mapping[identifiers.ColumnId, Expression],
+        allow_partial_bindings: bool = False,
+    ) -> PyObject:
+        return self
+
+    @property
+    def is_bijective(self) -> bool:
+        # () <-> value
+        return True
+
+    def transform_children(self, t: Callable[[Expression], Expression]) -> Expression:
+        return self
+
+
+@dataclasses.dataclass(frozen=True)
+class Call(Expression):
+    """An expression representing a scalar constant."""
+
+    # TODO: Further constrain?
+    callable: Expression
+    inputs: Tuple[Expression, ...]
+
+    @property
+    def column_references(
+        self,
+    ) -> Tuple[identifiers.ColumnId, ...]:
+        return tuple(
+            itertools.chain.from_iterable(
+                map(lambda x: x.column_references, self.children)
+            )
+        )
+
+    @property
+    def free_variables(self) -> set[str]:
+        return set(
+            itertools.chain.from_iterable(
+                map(lambda x: x.free_variables, self.children)
+            )
+        )
+
+    @property
+    def is_const(self) -> bool:
+        return False
+
+    @property
+    def children(self):
+        return (self.callable, *self.inputs)
+
+    @property
+    def nullable(self) -> bool:
+        return True
+
+    @property
+    def is_resolved(self) -> bool:
+        return False
+
+    @property
+    def output_type(self) -> dtypes.ExpressionType:
+        raise ValueError(f"Type of expression {self} has not been fixed.")
+
+    @property
+    def is_bijective(self) -> bool:
+        # TODO: Mark individual functions as bijective?
+        return False
+
+    @property
+    def deterministic(self) -> bool:
+        return True
+
+    def transform_children(self, t: Callable[[Expression], Expression]) -> Expression:
+        return dataclasses.replace(
+            self,
+            callable=t(self.callable),
+            inputs=tuple(t(input) for input in self.inputs),
+        )
+
+    def bind_variables(
+        self, bindings: Mapping[str, Expression], allow_partial_bindings: bool = False
+    ) -> Call:
+        return Call(
+            callable=self.callable.bind_variables(
+                bindings, allow_partial_bindings=allow_partial_bindings
+            ),
+            inputs=tuple(
+                input.bind_variables(
+                    bindings, allow_partial_bindings=allow_partial_bindings
+                )
+                for input in self.inputs
+            ),
+        )
+
+    def bind_refs(
+        self,
+        bindings: Mapping[identifiers.ColumnId, Expression],
+        allow_partial_bindings: bool = False,
+    ) -> Call:
+        return Call(
+            callable=self.callable.bind_refs(
+                bindings, allow_partial_bindings=allow_partial_bindings
+            ),
+            inputs=tuple(
+                input.bind_refs(bindings, allow_partial_bindings=allow_partial_bindings)
+                for input in self.inputs
+            ),
+        )
+
+
+# TODO: Mode that resolves free variable attrs as columns
+def resolve_py_exprs(expression: Expression, unpack_mode: bool = False) -> Expression:
+    """Replace all PyObject, attribute, call expressions. Bottom-up."""
+
+    def resolve_expr_if_call(expression: Expression) -> Expression:
+        if isinstance(expression, Call):
+            return resolve_call(expression)
+        return expression
+
+    # this function assumes attrs that become callables have been resolved
+    # also, we don't yet handle resolving attrs that are column accesses
+    def resolve_attrs(expression: Expression) -> Expression:
+        if isinstance(expression, GetAttr):
+            if isinstance(expression.input, Module):
+                # resolves things like Math.pi
+                return PyObject(getattr(expression.input.module, expression.attr))
+            if not unpack_mode and isinstance(
+                expression.input, UnboundVariableExpression
+            ):
+                return UnboundVariableExpression(expression.attr)
+        return expression
+
+    def resolve_pyobjs(expression: Expression) -> Expression:
+        if isinstance(expression, PyObject):
+            return const(expression.value)
+        return expression
+
+    wo_calls = expression.bottom_up(resolve_expr_if_call)
+    wo_attrs = wo_calls.bottom_up(resolve_attrs)
+    wo_pyobjs = wo_attrs.bottom_up(resolve_pyobjs)
+    return wo_pyobjs
+
+
+def resolve_call(call: Call) -> Expression:
+    callable = call.callable
+    if isinstance(callable, GetAttr):
+        attr = callable.attr
+        if isinstance(callable.input, Module):
+            fn = getattr(callable.input.module, attr)
+            if fn in python_op_maps.PYTHON_TO_BIGFRAMES:
+                op = python_op_maps.PYTHON_TO_BIGFRAMES[fn]
+                return OpExpression(op, call.inputs)
+            if fn in _CALLABLE_TO_OP:
+                op = _CALLABLE_TO_OP[fn]
+                return OpExpression(op, call.inputs)
+    elif isinstance(callable, PyObject):
+        if callable.value in python_op_maps.PYTHON_TO_BIGFRAMES:
+            op = python_op_maps.PYTHON_TO_BIGFRAMES[callable.value]
+            return OpExpression(op, call.inputs)
+        if callable.value in _BUILTIN_CALLABLES:
+            return OpExpression(_BUILTIN_CALLABLES[callable.value], call.inputs)
+
+    raise NotImplementedError(
+        f"No implementation available for call expression: {call}"
+    )
diff --git a/packages/bigframes/tests/unit/core/test_bytecode.py b/packages/bigframes/tests/unit/core/test_bytecode.py
new file mode 100644
index 000000000000..08903c8b2ba8
--- /dev/null
+++ b/packages/bigframes/tests/unit/core/test_bytecode.py
@@ -0,0 +1,89 @@
+# Copyright 2025 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import math
+
+import bigframes.core.expression as ex
+import bigframes.operations as ops
+from bigframes.core.bytecode import dis_to_expr
+
+
+def test_dis_to_expr_simple_arithmetic():
+    func = lambda row: row.x + 1
+    expr = dis_to_expr(func, unpack_mode=False)
+    assert expr is not None
+
+    expected = ops.add_op.as_expr(ex.free_var("x"), ex.const(1))
+    assert expr == expected
+
+
+def test_dis_to_expr_unpack_mode():
+    func = lambda col1, col2: col1 * col2
+    expr = dis_to_expr(func, unpack_mode=True)
+    assert expr is not None
+
+    expected = ops.mul_op.as_expr(ex.free_var("col1"), ex.free_var("col2"))
+    assert expr == expected
+
+
+def test_dis_to_expr_math_function():
+    func = lambda row: math.sin(row.x)
+    expr = dis_to_expr(func, unpack_mode=False)
+    assert expr is not None
+
+    expected = ops.numeric_ops.sin_op.as_expr(ex.free_var("x"))
+    assert expr == expected
+
+
+def test_dis_to_expr_negation():
+    func = lambda row: -row.x
+    expr = dis_to_expr(func, unpack_mode=False)
+    assert expr is not None
+
+    expected = ops.numeric_ops.neg_op.as_expr(ex.free_var("x"))
+    assert expr == expected
+
+
+def test_dis_to_expr_comparison():
+    func = lambda row: row.x == row.y
+    expr = dis_to_expr(func, unpack_mode=False)
+    assert expr is not None
+
+    expected = ops.comparison_ops.eq_op.as_expr(ex.free_var("x"), ex.free_var("y"))
+    assert expr == expected
+
+
+def test_dis_to_expr_unsupported():
+    # Control flow or unsupported structures should return None
+    def func_with_loop(row):
+        res = 0
+        for val in range(int(row.x)):
+            res += val
+        return res
+
+    expr = dis_to_expr(func_with_loop, unpack_mode=False)
+    assert expr is None
+
+
+global_none_val = None
+
+
+def test_dis_to_expr_global_none():
+    # Test resolving a global variable explicitly set to None
+    func = lambda row: row.x == global_none_val
+    expr = dis_to_expr(func, unpack_mode=False)
+    assert expr is not None
+
+    expected = ops.comparison_ops.eq_op.as_expr(ex.free_var("x"), ex.const(None))
+    assert expr == expected