diff --git a/app/models/user.rb b/app/models/user.rb
index 394f946..64f73f4 100644
--- a/app/models/user.rb
+++ b/app/models/user.rb
@@ -19,9 +19,11 @@ class User < ApplicationRecord
 
   enum :role, %i[contributor reviewer admin]
 
-  validates :email, presence: true, uniqueness: true
+  validates :email, presence: true, uniqueness: { case_sensitive: false }
   validates :password, length: { minimum: 12 }, if: -> { password.present? }
 
+  before_validation :normalize_email
+
   scope :by_role, ->(role) { where(role: role) if role.present? }
   scope :search_email, ->(q) { where("email LIKE ?", "%#{sanitize_sql_like(q)}%") if q.present? }
 
@@ -78,4 +80,10 @@ class User < ApplicationRecord
     return nil if user.nil? || user.remember_token_expired?
     user
   end
+
+  private
+
+  def normalize_email
+    self.email = email.downcase.strip if email.present?
+  end
 end