diff --git a/manifests/server/grant.pp b/manifests/server/grant.pp
index 2749e74f00..80ca540085 100644
--- a/manifests/server/grant.pp
+++ b/manifests/server/grant.pp
@@ -421,17 +421,22 @@
     }
   }
 
+  # Function like has_database_privilege() refer the PUBLIC pseudo role as 'public'
+  # So we need to replace 'PUBLIC' by 'public'.
+
   $_unless = $unless_function ? {
       false    => undef,
       'custom' => $custom_unless,
-      default  => "SELECT 1 WHERE ${unless_function}('${role}',
-                  '${_granted_object}${arguments}', '${unless_privilege}') = ${unless_is}",
+      default  => $role ? {
+        'PUBLIC' => "SELECT 1 WHERE ${unless_function}('public', '${_granted_object}${arguments}', '${unless_privilege}') = ${unless_is}",
+        default  => "SELECT 1 WHERE ${unless_function}('${role}', '${_granted_object}${arguments}', '${unless_privilege}') = ${unless_is}",
+      }
   }
 
   $_onlyif = $onlyif_function ? {
     'table_exists'    => "SELECT true FROM pg_tables WHERE tablename = '${_togrant_object}'",
     'language_exists' => "SELECT true from pg_language WHERE lanname = '${_togrant_object}'",
-    'role_exists'     => "SELECT 1 FROM pg_roles WHERE rolname = '${role}'",
+    'role_exists'     => "SELECT 1 FROM pg_roles WHERE rolname = '${role}' or '${role}' = 'PUBLIC'",
     'function_exists' => "SELECT true FROM pg_proc WHERE (oid::regprocedure)::text = '${_togrant_object}${arguments}'",
     default           => undef,
   }
diff --git a/spec/unit/defines/server/grant_spec.rb b/spec/unit/defines/server/grant_spec.rb
index 63d1e9e4ea..db4214b732 100644
--- a/spec/unit/defines/server/grant_spec.rb
+++ b/spec/unit/defines/server/grant_spec.rb
@@ -214,6 +214,34 @@ class {'postgresql::server':}
     end
   end
 
+  context 'with a role defined to PUBLIC' do
+    let :params do
+      {
+        db: 'test',
+        role: 'PUBLIC',
+        privilege: 'all',
+        object_name: ['myschema', 'mytable'],
+        object_type: 'table',
+      }
+    end
+
+    let :pre_condition do
+      <<-EOS
+      class {'postgresql::server':}
+      postgresql::server::role { 'test': }
+      EOS
+    end
+
+    it { is_expected.to compile.with_all_deps }
+    it { is_expected.to contain_postgresql__server__grant('test') }
+    it { is_expected.to contain_postgresql__server__role('test') }
+    it do
+      is_expected.to contain_postgresql_psql('grant:test')
+        .with_command(%r{GRANT ALL ON TABLE "myschema"."mytable" TO\s* "PUBLIC"}m)
+        .with_unless(%r{SELECT 1 WHERE has_table_privilege\('public',\s*'myschema.mytable', 'INSERT'\)}m)
+    end
+  end
+
   context 'function' do
     let :params do
       {