diff --git a/include/ceres/autodiff_cost_function.h b/include/ceres/autodiff_cost_function.h
index 207f0a416..993daf159 100644
--- a/include/ceres/autodiff_cost_function.h
+++ b/include/ceres/autodiff_cost_function.h
@@ -215,6 +215,8 @@ class AutoDiffCostFunction : public SizedCostFunction<kNumResiduals, Ns...> {
         jacobians);
   };
 
+  const CostFunctor & functor() const { return *functor_; }
+
  private:
   std::unique_ptr<CostFunctor> functor_;
   Ownership ownership_;
diff --git a/include/ceres/autodiff_first_order_function.h b/include/ceres/autodiff_first_order_function.h
index b98d84565..d0280b045 100644
--- a/include/ceres/autodiff_first_order_function.h
+++ b/include/ceres/autodiff_first_order_function.h
@@ -142,6 +142,8 @@ class AutoDiffFirstOrderFunction : public FirstOrderFunction {
 
   int NumParameters() const override { return kNumParameters; }
 
+  const FirstOrderFunctor & functor() const { return *functor_; }
+
  private:
   std::unique_ptr<FirstOrderFunctor> functor_;
 };
diff --git a/include/ceres/autodiff_local_parameterization.h b/include/ceres/autodiff_local_parameterization.h
index d694376fd..4ca4a501b 100644
--- a/include/ceres/autodiff_local_parameterization.h
+++ b/include/ceres/autodiff_local_parameterization.h
@@ -143,6 +143,8 @@ class AutoDiffLocalParameterization : public LocalParameterization {
   int GlobalSize() const override { return kGlobalSize; }
   int LocalSize() const override { return kLocalSize; }
 
+  const Functor & functor() const { return *functor_; }
+
  private:
   std::unique_ptr<Functor> functor_;
 };
diff --git a/include/ceres/autodiff_manifold.h b/include/ceres/autodiff_manifold.h
index 8a7601f02..96735335c 100644
--- a/include/ceres/autodiff_manifold.h
+++ b/include/ceres/autodiff_manifold.h
@@ -173,6 +173,8 @@ class AutoDiffManifold : public Manifold {
 
   bool MinusJacobian(const double* x, double* jacobian) const override;
 
+  const Functor & functor() const { return *functor_; }
+
  private:
   std::unique_ptr<Functor> functor_;
 };
diff --git a/include/ceres/numeric_diff_cost_function.h b/include/ceres/numeric_diff_cost_function.h
index cf7971cde..43fe768a4 100644
--- a/include/ceres/numeric_diff_cost_function.h
+++ b/include/ceres/numeric_diff_cost_function.h
@@ -246,6 +246,8 @@ class NumericDiffCostFunction : public SizedCostFunction<kNumResiduals, Ns...> {
     return true;
   }
 
+  const CostFunctor & functor() const { return *functor_; }
+
  private:
   std::unique_ptr<CostFunctor> functor_;
   Ownership ownership_;
diff --git a/include/ceres/numeric_diff_first_order_function.h b/include/ceres/numeric_diff_first_order_function.h
index 866383549..cd24c969c 100644
--- a/include/ceres/numeric_diff_first_order_function.h
+++ b/include/ceres/numeric_diff_first_order_function.h
@@ -151,6 +151,8 @@ class NumericDiffFirstOrderFunction : public FirstOrderFunction {
 
   int NumParameters() const override { return kNumParameters; }
 
+  const FirstOrderFunctor & functor() const { return *functor_; }
+
  private:
   std::unique_ptr<FirstOrderFunctor> functor_;
   Ownership ownership_;