diff --git a/app/lib/email_validator.rb b/app/lib/email_validator.rb
index 5578362..b45cddc 100644
--- a/app/lib/email_validator.rb
+++ b/app/lib/email_validator.rb
@@ -7,6 +7,7 @@ def self.email_is_allowed_basic?(email)
     return true if email.end_with? '@softwire.com'
     return true if email.end_with? '@fidusinfosec.com'
     return true if email.end_with? '@cyberis.com'
+    return true if email.end_with? '@pentestpartners.com'
     false
   end
 
@@ -25,6 +26,7 @@ def self.allowed_emails_regexp
       /([a-z0-9.\-\']+@softwire\.com,?\s*)/,
       /([a-z0-9.\-\']+@fidusinfosec\.com,?\s*)/,
       /([a-z0-9.\-\']+@cyberis\.com,?\s*)/,
+      /([a-z0-9.\-\']+@pentestpartners\.com,?\s*)/,
     )})+\z/
   end
 
diff --git a/test/lib/email_validator_test.rb b/test/lib/email_validator_test.rb
index 47537f0..a82e056 100644
--- a/test/lib/email_validator_test.rb
+++ b/test/lib/email_validator_test.rb
@@ -26,6 +26,11 @@ class EmailValidatorTest < ActiveSupport::TestCase
     assert EmailValidator.email_is_allowed_basic?(email)
   end
 
+  test 'Pentestpartners email addresses are allowed to sign in' do
+    email = 'fname.lname@pentestpartners.com'
+    assert EmailValidator.email_is_allowed_basic?(email)
+  end
+
   test 'Other email addresses are not allowed to sign in' do
     email = 'fname.lname@example.com'
     assert ! EmailValidator.email_is_allowed_basic?(email)
@@ -86,6 +91,11 @@ class EmailValidatorTest < ActiveSupport::TestCase
     assert_match EmailValidator.allowed_emails_regexp, email
   end
 
+  test 'Pentestpartners emails are matched by the allowed emails regexp' do
+    email = 'fname.lname@pentestpartners.com'
+    assert_match EmailValidator.allowed_emails_regexp, email
+  end
+
   test 'Emails with numbers in the local part are allowed' do
     email = 'fname.lname1@digital.cabinet-office.gov.uk'
     assert_match EmailValidator.allowed_emails_regexp, email