diff --git a/src/regexp/regexp-parser.cc b/src/regexp/regexp-parser.cc
index 726eb57ceb32..0b301fdeb983 100644
--- a/src/regexp/regexp-parser.cc
+++ b/src/regexp/regexp-parser.cc
@@ -14,6 +14,10 @@
 #include "src/regexp/jsregexp.h"
 #include "src/utils.h"
 
+// TODO(mathias): Remove this when we no longer need to check
+// `U_ICU_VERSION_MAJOR_NUM`.
+#include "unicode/uvernum.h"
+
 #ifdef V8_INTL_SUPPORT
 #include "unicode/uniset.h"
 #endif  // V8_INTL_SUPPORT