diff --git a/interpreter/operator_arithmetic.go b/interpreter/operator_arithmetic.go
index f5054e1..63e3d60 100644
--- a/interpreter/operator_arithmetic.go
+++ b/interpreter/operator_arithmetic.go
@@ -116,6 +116,20 @@ func evalCeiling(_ model.IUnaryExpression, obj result.Value) (result.Value, erro
 	return result.New(int32(math.Ceil(val)))
 }
 
+// Exp(argument Decimal) Decimal
+// https://cql.hl7.org/09-b-cqlreference.html#exp
+// Integer and long overloads are implicitly converted to decimal.
+func evalExpDecimal(_ model.IUnaryExpression, obj result.Value) (result.Value, error) {
+	if result.IsNull(obj) {
+		return result.New(nil)
+	}
+	val, err := result.ToFloat64(obj)
+	if err != nil {
+		return result.Value{}, err
+	}
+	return result.New(math.Exp(val))
+}
+
 // Floor(argument Decimal) Integer
 // https://cql.hl7.org/09-b-cqlreference.html#floor
 func evalFloor(_ model.IUnaryExpression, obj result.Value) (result.Value, error) {
diff --git a/interpreter/operator_dispatcher.go b/interpreter/operator_dispatcher.go
index 3c8a237..b68c327 100644
--- a/interpreter/operator_dispatcher.go
+++ b/interpreter/operator_dispatcher.go
@@ -143,6 +143,13 @@ func (i *interpreter) unaryOverloads(m model.IUnaryExpression) ([]convert.Overlo
 				Result:   evalCeiling,
 			},
 		}, nil
+	case *model.Exp:
+		return []convert.Overload[evalUnarySignature]{
+			{
+				Operands: []types.IType{types.Decimal},
+				Result:   evalExpDecimal,
+			},
+		}, nil
 	case *model.Floor:
 		return []convert.Overload[evalUnarySignature]{
 			{
diff --git a/model/model.go b/model/model.go
index f2f1050..fd05d05 100644
--- a/model/model.go
+++ b/model/model.go
@@ -617,6 +617,11 @@ type Is struct {
 
 var _ IUnaryExpression = &Is{}
 
+// Exp is https://cql.hl7.org/04-logicalspecification.html#exp.
+type Exp struct{ *UnaryExpression }
+
+var _ IUnaryExpression = &Exp{}
+
 // Negate is https://cql.hl7.org/04-logicalspecification.html#negate.
 type Negate struct{ *UnaryExpression }
 
@@ -1242,6 +1247,9 @@ func (a *ToTime) GetName() string { return "ToTime" }
 // GetName returns the name of the system operator.
 func (a *CalculateAge) GetName() string { return "CalculateAge" }
 
+// GetName returns the name of the system operator.
+func (a *Exp) GetName() string { return "Exp" }
+
 // GetName returns the name of the system operator.
 func (a *Negate) GetName() string { return "Negate" }
 
diff --git a/parser/operators.go b/parser/operators.go
index f9eefe1..9f2f5c2 100644
--- a/parser/operators.go
+++ b/parser/operators.go
@@ -676,6 +676,18 @@ func (p *Parser) loadSystemOperators() error {
 				}
 			},
 		},
+		{
+			name:     "Exp",
+			operands: [][]types.IType{{types.Decimal}},
+			model: func() model.IExpression {
+				return &model.Exp{
+					UnaryExpression: &model.UnaryExpression{
+						Expression: model.ResultType(types.Decimal),
+					},
+				}
+			},
+		},
+		// TODO: b/301606416 - Add support for Exp with Quantities, current behavior is ambiguous.
 		{
 			name:     "Floor",
 			operands: [][]types.IType{{types.Decimal}},
diff --git a/parser/operators_test.go b/parser/operators_test.go
index a098099..c4a5f43 100644
--- a/parser/operators_test.go
+++ b/parser/operators_test.go
@@ -495,6 +495,16 @@ func TestBuiltInFunctions(t *testing.T) {
 				},
 			},
 		},
+		{
+			name: "Arithmetic Exp",
+			cql:  "Exp(42.0)",
+			want: &model.Exp{
+				UnaryExpression: &model.UnaryExpression{
+					Operand:    model.NewLiteral("42.0", types.Decimal),
+					Expression: model.ResultType(types.Decimal),
+				},
+			},
+		},
 		{
 			name: "Arithmetic Floor",
 			cql:  "Floor(41.1)",
diff --git a/tests/enginetests/operator_arithmetic_test.go b/tests/enginetests/operator_arithmetic_test.go
index 915ef3b..e5d7a6d 100644
--- a/tests/enginetests/operator_arithmetic_test.go
+++ b/tests/enginetests/operator_arithmetic_test.go
@@ -241,6 +241,104 @@ func TestCeiling(t *testing.T) {
 	}
 }
 
+func TestExp(t *testing.T) {
+	tests := []struct {
+		name       string
+		cql        string
+		wantModel  model.IExpression
+		wantResult result.Value
+	}{
+		{
+			name: "Integer",
+			cql:  "Exp(4)",
+			wantModel: &model.Exp{
+				UnaryExpression: &model.UnaryExpression{
+					Operand: &model.ToDecimal{
+						UnaryExpression: &model.UnaryExpression{
+							Operand:    model.NewLiteral("4", types.Integer),
+							Expression: model.ResultType(types.Decimal),
+						},
+					},
+					Expression: model.ResultType(types.Decimal),
+				},
+			},
+			wantResult: newOrFatal(t, 54.598150033144236),
+		},
+		{
+			name:       "Positive Integer",
+			cql:        "Exp(2)",
+			wantResult: newOrFatal(t, 7.38905609893065),
+		},
+		{
+			name:       "Minimum Integer",
+			cql:        "Exp(-2147483648)",
+			wantResult: newOrFatal(t, 0.0),
+		},
+		{
+			name:       "Long",
+			cql:        "Exp(-4L)",
+			wantResult: newOrFatal(t, 0.01831563888873418),
+		},
+		{
+			name:       "Positive Long",
+			cql:        "Exp(2L)",
+			wantResult: newOrFatal(t, 7.38905609893065),
+		},
+		{
+			name:       "Minimum Long",
+			cql:        "Exp(-9223372036854775808L)",
+			wantResult: newOrFatal(t, 0.0),
+		},
+		{
+			name:       "Decimal zero",
+			cql:        "Exp(0.0)",
+			wantResult: newOrFatal(t, 1.0),
+		},
+		{
+			name:       "Decimal negative one",
+			cql:        "Exp(-1.0)",
+			wantResult: newOrFatal(t, 0.36787944117144233),
+		},
+		{
+			name:       "Positive Decimal one",
+			cql:        "Exp(1.0)",
+			wantResult: newOrFatal(t, 2.718281828459045),
+		},
+		{
+			name:       "Minimum Decimal",
+			cql:        "Exp(-99999999999999999999.99999999)",
+			wantResult: newOrFatal(t, 0.0),
+		},
+		{
+			name:       "Null",
+			cql:        "Exp(null as Decimal)",
+			wantResult: newOrFatal(t, nil),
+		},
+	}
+
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+			p := newFHIRParser(t)
+			parsedLibs, err := p.Libraries(context.Background(), wrapInLib(t, tc.cql), parser.Config{})
+			if err != nil {
+				t.Fatalf("Parse returned unexpected error: %v", err)
+			}
+			if diff := cmp.Diff(tc.wantModel, getTESTRESULTModel(t, parsedLibs)); tc.wantModel != nil && diff != "" {
+				t.Errorf("Parse diff (-want +got):\n%s", diff)
+			}
+
+			results, err := interpreter.Eval(context.Background(), parsedLibs, defaultInterpreterConfig(t, p))
+			if err != nil {
+				t.Fatalf("Eval returned unexpected error: %v", err)
+			}
+
+			if diff := cmp.Diff(tc.wantResult, getTESTRESULT(t, results), protocmp.Transform()); diff != "" {
+				t.Errorf("Eval diff (-want +got)\n%v", diff)
+			}
+		})
+	}
+}
+
 func TestFloor(t *testing.T) {
 	tests := []struct {
 		name       string
diff --git a/tests/spectests/exclusions/exclusions.go b/tests/spectests/exclusions/exclusions.go
index 59c22d4..c706145 100644
--- a/tests/spectests/exclusions/exclusions.go
+++ b/tests/spectests/exclusions/exclusions.go
@@ -58,7 +58,6 @@ func XMLTestFileExclusionDefinitions() map[string]XMLTestFileExclusions {
 		"CqlArithmeticFunctionsTest.xml": XMLTestFileExclusions{
 			GroupExcludes: []string{
 				// TODO: b/342061715 - unsupported operators.
-				"Exp",
 				"HighBoundary",
 				"Log",
 				"LowBoundary",
@@ -69,6 +68,8 @@ func XMLTestFileExclusionDefinitions() map[string]XMLTestFileExclusions {
 				"Divide103",
 				"Multiply1CMBy2CM",
 				"Power2DToNeg2DEquivalence",
+				"Exp1",    // Require Round support.
+				"ExpNeg1", // Require Round support.
 				"Ln1000",  // Require Round support.
 				"Ln1000D", // Require Round support.
 				// TODO: b/342061606 - Unit conversion is not supported.