diff --git a/src/backend/utils/adt/formatting.c b/src/backend/utils/adt/formatting.c
index 4e703d349f3..29ebc7831c5 100644
--- a/src/backend/utils/adt/formatting.c
+++ b/src/backend/utils/adt/formatting.c
@@ -84,6 +84,10 @@
 
 #ifdef USE_ICU
 #include <unicode/ustring.h>
+/* ICU might have a different definition of "bool", don't buy it */
+#ifdef bool
+#undef bool
+#endif
 #endif
 
 #include "catalog/pg_collation.h"
diff --git a/src/backend/utils/adt/pg_locale.c b/src/backend/utils/adt/pg_locale.c
index 7a12f84623e..bbf100e9fea 100644
--- a/src/backend/utils/adt/pg_locale.c
+++ b/src/backend/utils/adt/pg_locale.c
@@ -67,6 +67,10 @@
 
 #ifdef USE_ICU
 #include <unicode/ucnv.h>
+/* ICU might have a different definition of "bool", don't buy it */
+#ifdef bool
+#undef bool
+#endif
 #endif
 
 #ifdef WIN32
diff --git a/src/include/utils/pg_locale.h b/src/include/utils/pg_locale.h
index f3e04d4d8ce..21a047afbfa 100644
--- a/src/include/utils/pg_locale.h
+++ b/src/include/utils/pg_locale.h
@@ -17,6 +17,10 @@
 #endif
 #ifdef USE_ICU
 #include <unicode/ucol.h>
+/* ICU might have a different definition of "bool", don't buy it */
+#ifdef bool
+#undef bool
+#endif
 #endif
 
 #include "utils/guc.h"