diff --git a/src/catch2/catch_test_case_info.hpp b/src/catch2/catch_test_case_info.hpp
index 6cfc2aaf..52903ea6 100644
--- a/src/catch2/catch_test_case_info.hpp
+++ b/src/catch2/catch_test_case_info.hpp
@@ -17,6 +17,7 @@
 
 #include <string>
 #include <vector>
+#include <cstdint>
 
 #ifdef __clang__
 #pragma clang diagnostic push
diff --git a/src/catch2/internal/catch_string_manip.hpp b/src/catch2/internal/catch_string_manip.hpp
index dc58a336..c3da19d1 100644
--- a/src/catch2/internal/catch_string_manip.hpp
+++ b/src/catch2/internal/catch_string_manip.hpp
@@ -13,6 +13,7 @@
 #include <string>
 #include <iosfwd>
 #include <vector>
+#include <cstdint>
 
 namespace Catch {
 
diff --git a/src/catch2/internal/catch_xmlwriter.cpp b/src/catch2/internal/catch_xmlwriter.cpp
index 93758cba..aaeb3fc9 100644
--- a/src/catch2/internal/catch_xmlwriter.cpp
+++ b/src/catch2/internal/catch_xmlwriter.cpp
@@ -13,6 +13,7 @@
 
 #include <iomanip>
 #include <type_traits>
+#include <cstdint>
 
 namespace Catch {