diff --git a/api/models/User.js b/api/models/User.js
index e6ea9ce75..f7d07ade2 100644
--- a/api/models/User.js
+++ b/api/models/User.js
@@ -25,7 +25,7 @@ const userSchema = mongoose.Schema(
       type: String,
       lowercase: true,
       required: [true, 'can\'t be blank'],
-      match: [/^[a-zA-Z0-9_-]+$/, 'is invalid'],
+      match: [/^[a-zA-Z0-9_.-]+$/, 'is invalid'],
       index: true,
     },
     email: {
@@ -177,7 +177,7 @@ module.exports.validateUser = (user) => {
     username: Joi.string()
       .min(2)
       .max(80)
-      .regex(/^[a-zA-Z0-9_-]+$/)
+      .regex(/^[a-zA-Z0-9_.-]+$/)
       .required(),
     password: Joi.string().min(8).max(128).allow('').allow(null),
   };
diff --git a/api/strategies/validators.js b/api/strategies/validators.js
index 790500783..f105cae9b 100644
--- a/api/strategies/validators.js
+++ b/api/strategies/validators.js
@@ -11,7 +11,7 @@ const registerSchema = Joi.object().keys({
     .trim()
     .min(2)
     .max(20)
-    .regex(/^[a-zA-Z0-9_-]+$/)
+    .regex(/^[a-zA-Z0-9_.-]+$/)
     .required(),
   email: Joi.string().trim().email().required(),
   password: Joi.string().trim().min(8).max(128).required(),