diff --git a/src/mongocxx/events/heartbeat_failed_event.hpp b/src/mongocxx/events/heartbeat_failed_event.hpp
index 08cbe38d8d..8312fd0b02 100644
--- a/src/mongocxx/events/heartbeat_failed_event.hpp
+++ b/src/mongocxx/events/heartbeat_failed_event.hpp
@@ -14,6 +14,8 @@
 
 #pragma once
 
+#include <cstdint>
+
 #include <bsoncxx/stdx/string_view.hpp>
 
 #include <mongocxx/config/prelude.hpp>
diff --git a/src/mongocxx/events/heartbeat_started_event.hpp b/src/mongocxx/events/heartbeat_started_event.hpp
index e18c109530..7274c362e6 100644
--- a/src/mongocxx/events/heartbeat_started_event.hpp
+++ b/src/mongocxx/events/heartbeat_started_event.hpp
@@ -14,6 +14,8 @@
 
 #pragma once
 
+#include <cstdint>
+
 #include <bsoncxx/stdx/string_view.hpp>
 
 #include <mongocxx/config/prelude.hpp>
diff --git a/src/mongocxx/events/server_closed_event.hpp b/src/mongocxx/events/server_closed_event.hpp
index a0460835e7..d254ce6494 100644
--- a/src/mongocxx/events/server_closed_event.hpp
+++ b/src/mongocxx/events/server_closed_event.hpp
@@ -14,6 +14,8 @@
 
 #pragma once
 
+#include <cstdint>
+
 #include <bsoncxx/oid.hpp>
 #include <bsoncxx/stdx/string_view.hpp>
 
diff --git a/src/mongocxx/events/server_opening_event.hpp b/src/mongocxx/events/server_opening_event.hpp
index aa73fceab7..252a556423 100644
--- a/src/mongocxx/events/server_opening_event.hpp
+++ b/src/mongocxx/events/server_opening_event.hpp
@@ -14,6 +14,8 @@
 
 #pragma once
 
+#include <cstdint>
+
 #include <bsoncxx/oid.hpp>
 
 #include <mongocxx/config/prelude.hpp>
diff --git a/src/mongocxx/exception/error_code.hpp b/src/mongocxx/exception/error_code.hpp
index 24082c4a6c..8a6c11194b 100644
--- a/src/mongocxx/exception/error_code.hpp
+++ b/src/mongocxx/exception/error_code.hpp
@@ -14,6 +14,7 @@
 
 #pragma once
 
+#include <cstdint>
 #include <system_error>
 
 #include <mongocxx/config/prelude.hpp>
diff --git a/src/mongocxx/exception/server_error_code.hpp b/src/mongocxx/exception/server_error_code.hpp
index 5a0082ba99..cee7545674 100644
--- a/src/mongocxx/exception/server_error_code.hpp
+++ b/src/mongocxx/exception/server_error_code.hpp
@@ -14,6 +14,7 @@
 
 #pragma once
 
+#include <cstdint>
 #include <system_error>
 
 #include <mongocxx/config/prelude.hpp>