diff --git a/dart/optimizer/GenericMultiObjectiveProblem.cpp b/dart/optimizer/GenericMultiObjectiveProblem.cpp
index e58a57aa97..d62515739d 100644
--- a/dart/optimizer/GenericMultiObjectiveProblem.cpp
+++ b/dart/optimizer/GenericMultiObjectiveProblem.cpp
@@ -37,6 +37,7 @@
 #include "dart/optimizer/Function.hpp"
 
 #include <algorithm>
+#include <cassert>
 #include <limits>
 #include <numeric>
 
diff --git a/dart/optimizer/GradientDescentSolver.cpp b/dart/optimizer/GradientDescentSolver.cpp
index 6c92a32c30..d4b858a6c0 100644
--- a/dart/optimizer/GradientDescentSolver.cpp
+++ b/dart/optimizer/GradientDescentSolver.cpp
@@ -36,6 +36,7 @@
 #include "dart/math/Helpers.hpp"
 #include "dart/optimizer/Problem.hpp"
 
+#include <cassert>
 #include <iostream>
 
 namespace dart {
diff --git a/dart/optimizer/MultiObjectiveProblem.cpp b/dart/optimizer/MultiObjectiveProblem.cpp
index 6e86f0ee1a..e55e0bf99b 100644
--- a/dart/optimizer/MultiObjectiveProblem.cpp
+++ b/dart/optimizer/MultiObjectiveProblem.cpp
@@ -37,6 +37,7 @@
 #include "dart/optimizer/Function.hpp"
 
 #include <algorithm>
+#include <cassert>
 #include <limits>
 #include <numeric>
 
diff --git a/dart/optimizer/MultiObjectiveSolver.cpp b/dart/optimizer/MultiObjectiveSolver.cpp
index 4215f78e14..c0edbb5dc6 100644
--- a/dart/optimizer/MultiObjectiveSolver.cpp
+++ b/dart/optimizer/MultiObjectiveSolver.cpp
@@ -35,6 +35,7 @@
 #include "dart/common/Console.hpp"
 #include "dart/optimizer/MultiObjectiveProblem.hpp"
 
+#include <cassert>
 #include <fstream>
 
 namespace dart {
diff --git a/dart/optimizer/Population.cpp b/dart/optimizer/Population.cpp
index 0469683434..69e4b65141 100644
--- a/dart/optimizer/Population.cpp
+++ b/dart/optimizer/Population.cpp
@@ -35,6 +35,8 @@
 #include "dart/common/Console.hpp"
 #include "dart/math/Random.hpp"
 
+#include <cassert>
+
 namespace dart {
 namespace optimizer {
 
diff --git a/dart/optimizer/Problem.cpp b/dart/optimizer/Problem.cpp
index 8bf3317777..7dc20a0cc5 100644
--- a/dart/optimizer/Problem.cpp
+++ b/dart/optimizer/Problem.cpp
@@ -37,6 +37,7 @@
 #include "dart/optimizer/Function.hpp"
 
 #include <algorithm>
+#include <cassert>
 #include <limits>
 
 namespace dart {
diff --git a/dart/optimizer/ipopt/IpoptSolver.cpp b/dart/optimizer/ipopt/IpoptSolver.cpp
index 0762e1efed..e21260113c 100644
--- a/dart/optimizer/ipopt/IpoptSolver.cpp
+++ b/dart/optimizer/ipopt/IpoptSolver.cpp
@@ -38,6 +38,8 @@
 #include "dart/optimizer/Function.hpp"
 #include "dart/optimizer/Problem.hpp"
 
+#include <cassert>
+
 namespace dart {
 namespace optimizer {
 
diff --git a/dart/optimizer/nlopt/NloptSolver.cpp b/dart/optimizer/nlopt/NloptSolver.cpp
index 0adb336fcd..b5dcba5745 100644
--- a/dart/optimizer/nlopt/NloptSolver.cpp
+++ b/dart/optimizer/nlopt/NloptSolver.cpp
@@ -39,6 +39,7 @@
 
 #include <Eigen/Dense>
 
+#include <cassert>
 #include <memory>
 
 namespace dart {
diff --git a/dart/optimizer/pagmo/PagmoMultiObjectiveProblemAdaptor.cpp b/dart/optimizer/pagmo/PagmoMultiObjectiveProblemAdaptor.cpp
index aa3f5517c4..626955cbee 100644
--- a/dart/optimizer/pagmo/PagmoMultiObjectiveProblemAdaptor.cpp
+++ b/dart/optimizer/pagmo/PagmoMultiObjectiveProblemAdaptor.cpp
@@ -34,6 +34,8 @@
 
 #include "dart/optimizer/pagmo/PagmoUtils.hpp"
 
+#include <cassert>
+
 namespace dart {
 namespace optimizer {