diff --git a/app/controllers/submissions_controller.rb b/app/controllers/submissions_controller.rb
--- a/app/controllers/submissions_controller.rb
+++ b/app/controllers/submissions_controller.rb
@@ -94,9 +94,8 @@
 
   def submission_authorization
     #admin always has privileged
-    if @current_user.admin?
-      return true
-    end
+    return true if @current_user.admin?
+    return true if @current_user.has_role?('TA') && (['show','download'].include? action_name)
 
     sub = Submission.find(params[:id])
     if @current_user.available_problems.include? sub.problem
diff --git a/app/controllers/user_admin_controller.rb b/app/controllers/user_admin_controller.rb
--- a/app/controllers/user_admin_controller.rb
+++ b/app/controllers/user_admin_controller.rb
@@ -362,36 +362,33 @@
   # admin management
 
   def admin
-    @admins = User.all.find_all {|user| user.admin? }
+    @admins = Role.where(name: 'admin').take.users
+    @tas = Role.where(name: 'ta').take.users
   end
 
-  def grant_admin
-    login = params[:login]
-    user = User.find_by_login(login)
-    if user!=nil
-      admin_role = Role.find_by_name('admin')
-      user.roles << admin_role
-    else
-      flash[:notice] = 'Unknown user'
+  def modify_role
+    user = User.find_by_login(params[:login])
+    role = Role.find_by_name(params[:role])
+    unless user && role
+      flash[:error] = 'Unknown user or role'
+      redirect_to admin_user_admin_index_path
+      return
     end
-    flash[:notice] = 'User added as admins'
-    redirect_to :action => 'admin'
-  end
-
-  def revoke_admin
-    user = User.find(params[:id])
-    if user==nil
-      flash[:notice] = 'Unknown user'
-      redirect_to :action => 'admin' and return
-    elsif user.login == 'root'
-      flash[:notice] = 'You cannot revoke admisnistrator permission from root.'
-      redirect_to :action => 'admin' and return
+    if params[:commit] == 'Grant'
+      #grant role
+      user.roles << role
+      flash[:notice] = "User '#{user.login}' has been granted the role '#{role.name}'"
+    else
+      #revoke role
+      if user.login == 'root' && role.name == 'admin'
+        flash[:error] = 'You cannot revoke admisnistrator permission from root.'
+        redirect_to admin_user_admin_index_path
+        return
+      end
+      user.roles.delete(role)
+      flash[:notice] = "The role '#{role.name}' has been revoked from User '#{user.login}'"
     end
-
-    admin_role = Role.find_by_name('admin')
-    user.roles.delete(admin_role)
-    flash[:notice] = 'User permission revoked'
-    redirect_to :action => 'admin'
+    redirect_to admin_user_admin_index_path
   end
 
   # mass mailing
diff --git a/app/models/user.rb b/app/models/user.rb
--- a/app/models/user.rb
+++ b/app/models/user.rb
@@ -81,7 +81,11 @@
   end
 
   def admin?
-    self.roles.where(name: 'admin').count > 0
+    has_role?('admin')
+  end
+
+  def has_role?(role)
+    self.roles.where(name: role).count > 0
   end
 
   def email_for_editing
diff --git a/app/views/user_admin/admin.html.haml b/app/views/user_admin/admin.html.haml
--- a/app/views/user_admin/admin.html.haml
+++ b/app/views/user_admin/admin.html.haml
@@ -1,25 +1,54 @@
-%h1 Administrators
+%h1 Modify Role
+.row
+  .col-md-6
+    %h4 Administrators
+    = form_tag modify_role_user_admin_index_path, method: 'post', class: 'form-inline' do
+      = hidden_field_tag :role, 'admin'
+      .form-group
+        = label_tag :login, 'Grant admin role to:'
+        = text_field_tag 'login',nil, class: 'form-control'
+      .form-group
+        = submit_tag 'Grant', class: 'btn btn-primary'
+    %br
+    %table.table.table-condense.table-hover.table-striped.table-bordered
+      %thead{:class => 'info-head'}
+        %th #
+        %th Login
+        %th Full name
+        %th 
+      - @admins.each_with_index do |user, i|
+        %tr
+          %td= i+1
+          %td= user.login
+          %td= user.full_name
+          %td
+            - if user.login!='root'
+              = link_to '[revoke]', modify_role_user_admin_index_path( login: user.login, role: 'admin', commit: 'revoke')
+  .col-md-6
+    %h4 Teacher Assistants (TA)
+    = form_tag modify_role_user_admin_index_path, method: 'post', class: 'form-inline' do
+      = hidden_field_tag :role, 'TA'
+      .form-group
+        = label_tag :login, 'Grant TA role to:'
+        = text_field_tag 'login',nil, class: 'form-control'
+      .form-group
+        = submit_tag 'Grant', class: 'btn btn-primary'
+    %br
+    %table.table.table-condense.table-hover.table-striped.table-bordered
+      %thead{:class => 'info-head'}
+        %th #
+        %th Login
+        %th Full name
+        %th 
+      - @tas.each_with_index do |user, i|
+        %tr
+          %td= i+1
+          %td= user.login
+          %td= user.full_name
+          %td
+            - if user.login!='root'
+              = link_to '[revoke]', modify_role_user_admin_index_path( login: user.login, role: 'TA', commit: 'revoke')
 
-%table{:class => 'info'}
-  %tr{:class => 'info-head'}
-    %th #
-    %th Login
-    %th Full name
-    %th 
-  - @admins.each_with_index do |user, i|
-    %tr
-      %td= i+1
-      %td= user.login
-      %td= user.full_name
-      %td
-        - if user.login!='root'
-          = link_to '[revoke]', :action => 'revoke_admin', :id => user.id
-%hr
-
-= form_tag :action => 'grant_admin' do
-  = label_tag :login, 'Grant admin permission to:'
-  = text_field_tag 'login',nil, class: 'input-field'
-  = submit_tag 'Grant', class: 'btn btn-primary'
 
 %hr/
 = link_to '[go back to index]', :action => 'index'
diff --git a/config/routes.rb b/config/routes.rb
--- a/config/routes.rb
+++ b/config/routes.rb
@@ -113,8 +113,7 @@
       get 'admin'
       get 'active'
       get 'mass_mailing'
-      get 'revoke_admin'
-      post 'grant_admin'
+      match 'modify_role', via: [:get, :post]
       match 'create_from_list', via: [:get, :post]
       match 'random_all_passwords', via: [:get, :post]
     end
diff --git a/db/seeds.rb b/db/seeds.rb
--- a/db/seeds.rb
+++ b/db/seeds.rb
@@ -225,6 +225,7 @@
 end
 
 def seed_roles
+  Role.find_or_create_by(name: 'TA')
   return if Role.find_by_name('admin')
 
   role = Role.create(:name => 'admin')