diff --git a/ext/intl/calendar/gregoriancalendar_methods.cpp b/ext/intl/calendar/gregoriancalendar_methods.cpp
index 46c34b5efe6af..8796e01f6381f 100644
--- a/ext/intl/calendar/gregoriancalendar_methods.cpp
+++ b/ext/intl/calendar/gregoriancalendar_methods.cpp
@@ -17,6 +17,7 @@
 #endif
 
 #include "../intl_cppshims.h"
+#include <memory>
 
 #include <unicode/locid.h>
 #include <unicode/calendar.h>
diff --git a/ext/intl/dateformat/dateformat_format_object.cpp b/ext/intl/dateformat/dateformat_format_object.cpp
index da306c5896be2..a5113ce4cf9e1 100644
--- a/ext/intl/dateformat/dateformat_format_object.cpp
+++ b/ext/intl/dateformat/dateformat_format_object.cpp
@@ -13,6 +13,7 @@
 */
 
 #include "../intl_cppshims.h"
+#include <memory>
 
 #include <unicode/calendar.h>
 #include <unicode/gregocal.h>
diff --git a/ext/intl/timezone/timezone_class.cpp b/ext/intl/timezone/timezone_class.cpp
index 0cc6e1378729f..0737d99423110 100644
--- a/ext/intl/timezone/timezone_class.cpp
+++ b/ext/intl/timezone/timezone_class.cpp
@@ -18,6 +18,7 @@
 #endif
 
 #include "../intl_cppshims.h"
+#include <memory>
 
 #include <unicode/timezone.h>
 #include <unicode/calendar.h>