diff --git a/lib/hex/scm.ex b/lib/hex/scm.ex
index ed9b1f5a..bd4febd3 100644
--- a/lib/hex/scm.ex
+++ b/lib/hex/scm.ex
@@ -116,6 +116,16 @@ defmodule Hex.SCM do
     end
   end
 
+  # https://hexdocs.pm/mix/Mix.Tasks.Deps.html#module-dependency-definition-options
+  mix_keys = ~w[app env compile optional only targets override manager runtime system_env]a
+
+  # https://hex.pm/docs/usage#options
+  hex_keys = ~w[hex repo organization]a
+
+  internal_keys = ~w[dest lock build]a
+
+  @allowed_keys mix_keys ++ hex_keys ++ internal_keys
+
   def update(opts) do
     Registry.open()
 
@@ -125,6 +135,15 @@ defmodule Hex.SCM do
     repo = opts[:repo] || "hexpm"
     path = cache_path(repo, name, lock.version)
 
+    unknown_options = Keyword.keys(opts) -- @allowed_keys
+
+    if unknown_options != [] do
+      Hex.Shell.warn(
+        "#{name} is using unknown options: " <>
+          Enum.map_join(unknown_options, ", ", &inspect/1)
+      )
+    end
+
     case Hex.Parallel.await(:hex_fetcher, {:tarball, repo, name, lock.version}, @fetch_timeout) do
       {:ok, :cached} ->
         Hex.Shell.debug("  Using locally cached package (#{path})")
diff --git a/test/hex/mix_task_test.exs b/test/hex/mix_task_test.exs
index 3d07fc29..96a20328 100644
--- a/test/hex/mix_task_test.exs
+++ b/test/hex/mix_task_test.exs
@@ -229,6 +229,19 @@ defmodule Hex.MixTaskTest do
     end
   end
 
+  defmodule WithUnknownOptions do
+    def project do
+      [
+        app: :with_unknown_options,
+        version: "0.1.0",
+        consolidate_protocols: false,
+        deps: [
+          {:ex_doc, dir: "/bad", typo: true}
+        ]
+      ]
+    end
+  end
+
   defmodule WithNonMatchingRequirement do
     def project do
       [
@@ -882,6 +895,22 @@ defmodule Hex.MixTaskTest do
     end)
   end
 
+  test "deps.get with unknown options" do
+    Mix.Project.push(WithUnknownOptions)
+
+    in_tmp(fn ->
+      Hex.State.put(:cache_home, File.cwd!())
+
+      Mix.Task.run("deps.get")
+
+      assert_received {:mix_shell, :info,
+                       ["\e[33mex_doc is missing its version requirement, use \">= 0.0.0\"" <> _]}
+
+      assert_received {:mix_shell, :info,
+                       ["\e[33mex_doc is using unknown options: :dir, :typo\e[0m"]}
+    end)
+  end
+
   defp old_lock_tuple(lock_tuple) do
     {elem(lock_tuple, 0), elem(lock_tuple, 1), elem(lock_tuple, 2), elem(lock_tuple, 3)}
   end