diff --git a/rtc_base/third_party/base64/base64.h b/rtc_base/third_party/base64/base64.h
index 4190a79dc0..5d42513323 100644
--- a/rtc_base/third_party/base64/base64.h
+++ b/rtc_base/third_party/base64/base64.h
@@ -12,6 +12,8 @@
 #ifndef RTC_BASE_THIRD_PARTY_BASE64_BASE64_H_
 #define RTC_BASE_THIRD_PARTY_BASE64_BASE64_H_
 
+#include <cstddef>
+#include <cstdint>
 #include <string>
 #include <vector>