diff --git a/__tests__/lib/cli/envAlias.js b/__tests__/lib/cli/envAlias.js
index 690db9d5d..d0b70b706 100644
--- a/__tests__/lib/cli/envAlias.js
+++ b/__tests__/lib/cli/envAlias.js
@@ -17,6 +17,7 @@ describe( 'utils/cli/envAlias', () => {
 			'@1',
 			'@1.env',
 			'@2.MixedCaseEnv',
+			'@xxx.production_test',
 		] )( 'should identify valid aliases - %p', alias => {
 			expect( isAlias( alias ) ).toBe( true );
 		} );
diff --git a/src/lib/cli/envAlias.ts b/src/lib/cli/envAlias.ts
index c295500ed..1360feb26 100644
--- a/src/lib/cli/envAlias.ts
+++ b/src/lib/cli/envAlias.ts
@@ -1,5 +1,5 @@
 export function isAlias( alias: string ): boolean {
-	return /^@[A-Za-z0-9.-]+$/.test( alias );
+	return /^@[A-Za-z0-9._-]+$/.test( alias );
 }
 
 export function parseEnvAlias( alias: string ) {