diff --git a/src/bin/psql/command.c b/src/bin/psql/command.c
index cb94ce3..26089352 100644
--- a/src/bin/psql/command.c
+++ b/src/bin/psql/command.c
@@ -2711,7 +2711,7 @@ pset_bool_string(bool val)
 static char *
 pset_quoted_string(const char *str)
 {
-	char	   *ret = pg_malloc(strlen(str) * 2 + 2);
+	char	   *ret = pg_malloc(strlen(str) * 2 + 3);
 	char	   *r = ret;
 
 	*r++ = '\'';