diff --git a/src/hash_utils.h b/src/hash_utils.h
index 28241d1570a4..1fa418ff5188 100644
--- a/src/hash_utils.h
+++ b/src/hash_utils.h
@@ -2,6 +2,7 @@
 #ifndef CATA_SRC_HASH_UTILS_H
 #define CATA_SRC_HASH_UTILS_H
 
+#include <cstdint>
 #include <functional>
 
 // Support for hashing standard types.
diff --git a/src/om_direction.h b/src/om_direction.h
index 04c4d41d5c58..14ff7d55a23e 100644
--- a/src/om_direction.h
+++ b/src/om_direction.h
@@ -2,6 +2,7 @@
 #ifndef CATA_SRC_OM_DIRECTION_H
 #define CATA_SRC_OM_DIRECTION_H
 
+#include <cstdint>
 #include <climits>
 #include <array>
 #include <string>
diff --git a/src/units_mass.h b/src/units_mass.h
index abf7ee91d0ca..a99949e961df 100644
--- a/src/units_mass.h
+++ b/src/units_mass.h
@@ -2,6 +2,7 @@
 #ifndef CATA_SRC_UNITS_MASS_H
 #define CATA_SRC_UNITS_MASS_H
 
+#include <cstdint>
 #include <algorithm>
 
 #include "units_def.h"