diff --git a/app/views/protocols/index/_external_protocols_tab.html.erb b/app/views/protocols/index/_external_protocols_tab.html.erb
index 515525f6b..20044e4e2 100644
--- a/app/views/protocols/index/_external_protocols_tab.html.erb
+++ b/app/views/protocols/index/_external_protocols_tab.html.erb
@@ -28,8 +28,12 @@
           <span><%= t('protocols.index.external_protocols.sort_by.title') %></span>
           <div class='btn-group' data-toggle='buttons'>
             <label class='btn btn-link active'>
-              <input type='radio' name='sort_by' id='alphabetically' value='alpha' checked>
-              <%= t('protocols.index.external_protocols.sort_by.alphabetically') %>
+              <input type='radio' name='sort_by' id='alphabetically-asc' value='alpha_asc' checked>
+              <%= t('protocols.index.external_protocols.sort_by.alphabetically-asc') %>
+            </label>
+            <label class='btn btn-link'>
+              <input type='radio' name='sort_by' id='alphabetically-desc' value='alpha_desc'>
+              <%= t('protocols.index.external_protocols.sort_by.alphabetically-desc') %>
             </label>
             <label class='btn btn-link'>
               <input type='radio' name='sort_by' id='newest' value='newest'>
diff --git a/config/initializers/constants.rb b/config/initializers/constants.rb
index c2b8cc11f..876b62f2a 100644
--- a/config/initializers/constants.rb
+++ b/config/initializers/constants.rb
@@ -204,7 +204,8 @@ class Constants
     default_timeout: 10,
     debug_level: :debug,
     sort_mappings: {
-      alpha: { order_field: :name, order_dir: :asc },
+      alpha_asc: { order_field: :name, order_dir: :asc },
+      alpha_desc: { order_field: :name, order_dir: :desc },
       newest: { order_field: :date, order_dir: :desc },
       oldest: { order_field: :date, order_dir: :asc }
     },
diff --git a/config/locales/en.yml b/config/locales/en.yml
index 26145a01f..c6764fc25 100644
--- a/config/locales/en.yml
+++ b/config/locales/en.yml
@@ -1741,7 +1741,8 @@ en:
         protocolsio_title: 'Protocols.io'
         sort_by:
           title: 'Show first:'
-          alphabetically: 'alphabetically'
+          alphabetically-asc: 'A-Z'
+          alphabetically-desc: 'Z-A'
           newest: 'newest'
           oldest: 'oldest'
         list_panel: