diff --git a/include/xlnt/cell/phonetic_run.hpp b/include/xlnt/cell/phonetic_run.hpp
index cbf62ea7a..9f20384eb 100644
--- a/include/xlnt/cell/phonetic_run.hpp
+++ b/include/xlnt/cell/phonetic_run.hpp
@@ -24,6 +24,7 @@
 #pragma once
 
 #include <string>
+#include <cstdint>
 
 #include <xlnt/xlnt_config.hpp>
 
diff --git a/include/xlnt/utils/variant.hpp b/include/xlnt/utils/variant.hpp
index 213625789..0f47234a1 100644
--- a/include/xlnt/utils/variant.hpp
+++ b/include/xlnt/utils/variant.hpp
@@ -25,6 +25,7 @@
 
 #include <string>
 #include <vector>
+#include <cstdint>
 
 #include <xlnt/xlnt_config.hpp>
 
diff --git a/source/utils/time.cpp b/source/utils/time.cpp
index 89ec89148..6d0f3220f 100644
--- a/source/utils/time.cpp
+++ b/source/utils/time.cpp
@@ -22,6 +22,7 @@
 // @author: see AUTHORS file
 #include <cmath>
 #include <ctime>
+#include <cstdint>
 
 #include <xlnt/utils/time.hpp>
 
diff --git a/source/utils/timedelta.cpp b/source/utils/timedelta.cpp
index a263e6855..ef065efd5 100644
--- a/source/utils/timedelta.cpp
+++ b/source/utils/timedelta.cpp
@@ -22,6 +22,7 @@
 // @author: see AUTHORS file
 #include <cmath>
 #include <ctime>
+#include <cstdint>
 
 #include <xlnt/utils/timedelta.hpp>