diff --git a/string_utils/string_utils.go b/string_utils/string_utils.go
index f545ea443c6195f6ebd96f677af784077a886b40..ac6ddd71da1d0398376f20a59625100c38513cf0 100644
--- a/string_utils/string_utils.go
+++ b/string_utils/string_utils.go
@@ -83,7 +83,7 @@ func IsAlphaNumericOrDash(str string) bool {
 }
 
 func IsValidUsername(str string) bool {
-	regex := regexp.MustCompile("^[a-zA-Z0-9-.@+]*$")
+	regex := regexp.MustCompile("^[a-zA-Z0-9-.@+_]*$")
 	return regex.MatchString(str)
 }