diff --git a/lib/base/dictionary.cpp b/lib/base/dictionary.cpp
index 8472cc68d..50fb5d750 100644
--- a/lib/base/dictionary.cpp
+++ b/lib/base/dictionary.cpp
@@ -22,6 +22,7 @@
 #include "base/debug.hpp"
 #include "base/primitivetype.hpp"
 #include "base/configwriter.hpp"
+#include <sstream>
 
 using namespace icinga;
 
diff --git a/lib/base/process.hpp b/lib/base/process.hpp
index 8dc9b7ca2..259f19e33 100644
--- a/lib/base/process.hpp
+++ b/lib/base/process.hpp
@@ -25,6 +25,7 @@
 #include <iosfwd>
 #include <deque>
 #include <vector>
+#include <sstream>
 
 namespace icinga
 {