diff --git a/src/backend/commands/collationcmds.c b/src/backend/commands/collationcmds.c
index 5a2ba56cec..9b8a259eb2 100644
--- a/src/backend/commands/collationcmds.c
+++ b/src/backend/commands/collationcmds.c
@@ -215,7 +215,19 @@ DefineCollation(ParseState *pstate, List *names, List *parameters, bool if_not_e
 	if (!fromEl)
 	{
 		if (collprovider == COLLPROVIDER_ICU)
+		{
+			/*
+			 * While an ICU collation can support various encodings, only
+			 * allow one to be created when the current database's encoding is
+			 * supported.  Otherwise we get surprising behaviors like not
+			 * being able to drop the collation.
+			 */
+			if (!is_encoding_supported_by_icu(GetDatabaseEncoding()))
+				ereport(ERROR,
+						(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+						 errmsg("current database's encoding is not supported with this provider")));
 			collencoding = -1;
+		}
 		else
 		{
 			collencoding = GetDatabaseEncoding();