diff --git a/index_set.hpp b/index_set.hpp
index 7a229177..9cd9257d 100644
--- a/index_set.hpp
+++ b/index_set.hpp
@@ -19,6 +19,7 @@
 #ifndef REALM_INDEX_SET_HPP
 #define REALM_INDEX_SET_HPP
 
+#include <cstdlib>
 #include <vector>
 
 namespace realm {
diff --git a/schema.hpp b/schema.hpp
index 4d9c7bed..b8d50777 100644
--- a/schema.hpp
+++ b/schema.hpp
@@ -19,6 +19,7 @@
 #ifndef REALM_SCHEMA_HPP
 #define REALM_SCHEMA_HPP
 
+#include <string>
 #include <vector>
 
 namespace realm {
diff --git a/shared_realm.hpp b/shared_realm.hpp
index 0503282a..67b4f3a5 100644
--- a/shared_realm.hpp
+++ b/shared_realm.hpp
@@ -19,12 +19,13 @@
 #ifndef REALM_REALM_HPP
 #define REALM_REALM_HPP
 
+#include "object_store.hpp"
+
 #include <memory>
+#include <mutex>
 #include <thread>
 #include <vector>
 
-#include "object_store.hpp"
-
 namespace realm {
     class ClientHistory;
     class Realm;
@@ -166,7 +167,7 @@ namespace realm {
             std::runtime_error(std::move(message)), m_kind(kind), m_path(std::move(path)) {}
         Kind kind() const { return m_kind; }
         const std::string& path() const { return m_path; }
-        
+
     private:
         Kind m_kind;
         std::string m_path;