diff --git a/app/controllers/application_controller.rb b/app/controllers/application_controller.rb
index 50e9c8b5..aa4438f5 100644
--- a/app/controllers/application_controller.rb
+++ b/app/controllers/application_controller.rb
@@ -1,23 +1,16 @@
 class ApplicationController < ActionController::Base
   helper Mitlibraries::Theme::Engine.helpers
 
-  # Set active tab based on feature flag and params
-  # Also stores the last used tab in a cookie for future searches when passed via params.
-  # We set this in a session cookie to persist user preference across searches.
-  # Clicking on a different tab will update the cookie.
+  # Set active tab based on params (no persistent cookie). This intentionally
+  # avoids storing the user's last-used tab in a cookie per UXWS request.
   def set_active_tab
     # GeoData doesn't use the tab system.
     return if Feature.enabled?(:geodata)
 
     @active_tab = if params[:tab].present? && valid_tab?(params[:tab])
-                    # If params[:tab] is set and valid, use it and set session
-                    cookies[:last_tab] = params[:tab]
-                  elsif cookies[:last_tab].present? && valid_tab?(cookies[:last_tab])
-                    # Otherwise, check for last used tab in session if valid
-                    cookies[:last_tab]
+                    params[:tab]
                   else
-                    # Default behavior when no tab is specified in params or session
-                    cookies[:last_tab] = 'all'
+                    'all'
                   end
   end
 
diff --git a/test/controllers/application_controller_test.rb b/test/controllers/application_controller_test.rb
index 9f926988..af054e04 100644
--- a/test/controllers/application_controller_test.rb
+++ b/test/controllers/application_controller_test.rb
@@ -2,8 +2,6 @@
 
 class ApplicationControllerTest < ActionDispatch::IntegrationTest
   test 'set_active_tab sets default to all when no feature flag or params' do
-    assert_nil cookies[:last_tab]
-
     get root_path
     assert_select '#tab-to-target' do
       assert_select '[value=?]', 'all'
@@ -11,8 +9,6 @@ class ApplicationControllerTest < ActionDispatch::IntegrationTest
       refute_select '[value=?]', 'primo'
       refute_select '[value=?]', 'timdex'
     end
-
-    assert_equal cookies[:last_tab], 'all'
   end
 
   test 'set_active_tab sets to geodata when feature flag enabled' do
@@ -37,8 +33,7 @@ class ApplicationControllerTest < ActionDispatch::IntegrationTest
     end
   end
 
-  test 'set_active_tab sets to param tab when provided even if cookie is set and updates cookie' do
-    cookies[:last_tab] = 'timdex'
+  test 'set_active_tab sets to param tab when provided (param takes precedence)' do
     get root_path, params: { tab: 'primo' }
 
     assert_select '#tab-to-target' do
@@ -47,17 +42,14 @@ class ApplicationControllerTest < ActionDispatch::IntegrationTest
       refute_select '[value=?]', 'timdex'
       refute_select '[value=?]', 'all'
     end
-
-    assert_equal cookies[:last_tab], 'primo'
   end
 
-  test 'set_active_tab uses cookie last_tab when no param provided' do
-    cookies[:last_tab] = 'timdex'
+  test 'set_active_tab defaults to all when no param provided' do
     get root_path
     assert_select '#tab-to-target' do
-      refute_select '[value=?]', 'all'
+      assert_select '[value=?]', 'all'
       refute_select '[value=?]', 'primo'
-      assert_select '[value=?]', 'timdex'
+      refute_select '[value=?]', 'timdex'
     end
   end
 
@@ -65,7 +57,7 @@ class ApplicationControllerTest < ActionDispatch::IntegrationTest
     app_controller = ApplicationController.new
 
     assert app_controller.send(:valid_tab?, 'primo')
-    assert app_controller.send(:valid_tab?, 'timdex') 
+    assert app_controller.send(:valid_tab?, 'timdex')
     assert app_controller.send(:valid_tab?, 'all')
   end
 
@@ -84,43 +76,31 @@ class ApplicationControllerTest < ActionDispatch::IntegrationTest
       assert_select '[value=?]', 'all'
       refute_select '[value=?]', 'invalid_tab'
     end
-
-    assert_equal cookies[:last_tab], 'all'
   end
 
   test 'set_active_tab ignores invalid cookie value and uses default' do
-    cookies[:last_tab] = 'invalid_cookie_value'
     get root_path
 
     assert_select '#tab-to-target' do
       assert_select '[value=?]', 'all'
       refute_select '[value=?]', 'invalid_cookie_value'
     end
-
-    assert_equal cookies[:last_tab], 'all'
   end
 
   test 'set_active_tab prioritizes valid param over invalid cookie' do
-    cookies[:last_tab] = 'invalid_cookie'
     get root_path, params: { tab: 'timdex' }
 
     assert_select '#tab-to-target' do
-      refute_select '[value=?]', 'invalid_cookie'
       assert_select '[value=?]', 'timdex'
     end
-
-    assert_equal cookies[:last_tab], 'timdex'
   end
 
-  test 'set_active_tab falls back to valid cookie when param is invalid' do
-    cookies[:last_tab] = 'primo'
+  test 'set_active_tab with invalid param uses default' do
     get root_path, params: { tab: 'foo' }
 
     assert_select '#tab-to-target' do
       refute_select '[value=?]', 'foo'
-      assert_select '[value=?]', 'primo'
+      assert_select '[value=?]', 'all'
     end
-
-    assert_equal cookies[:last_tab], 'primo'
   end
 end
diff --git a/test/controllers/application_controller_unit_test.rb b/test/controllers/application_controller_unit_test.rb
index 99b3eace..47fd1f7c 100644
--- a/test/controllers/application_controller_unit_test.rb
+++ b/test/controllers/application_controller_unit_test.rb
@@ -29,37 +29,20 @@ class ApplicationControllerUnitTest < ActionController::TestCase
     refute @controller.send(:valid_tab?, '')
   end
 
-  test 'set_active_tab defaults @active_tab to all when no params or cookies are set' do
+  test 'set_active_tab defaults @active_tab to all when no params are set' do
     @controller.stubs(:params).returns({})
-    @controller.stubs(:cookies).returns({})
     @controller.set_active_tab
     assert_equal 'all', @controller.instance_variable_get(:@active_tab)
   end
 
   test 'set_active_tab sets @active_tab to tab when tab params is valid' do
     @controller.stubs(:params).returns({ tab: 'primo' })
-    @controller.stubs(:cookies).returns({})
     @controller.set_active_tab
     assert_equal 'primo', @controller.instance_variable_get(:@active_tab)
   end
 
-  test 'set_active_tab sets @active_tab to all when tab params is invalid and no cookie is set' do
+  test 'set_active_tab sets @active_tab to all when tab param is invalid' do
     @controller.stubs(:params).returns({ tab: 'supertab' })
-    @controller.stubs(:cookies).returns({})
-    @controller.set_active_tab
-    assert_equal 'all', @controller.instance_variable_get(:@active_tab)
-  end
-
-  test 'set_active_tab sets @active_tab to cookie value when tab params is invalid and valid cookie is set' do
-    @controller.stubs(:params).returns({ tab: 'supertab' })
-    @controller.stubs(:cookies).returns({ last_tab: 'timdex' })
-    @controller.set_active_tab
-    assert_equal 'timdex', @controller.instance_variable_get(:@active_tab)
-  end
-
-  test 'set_active_tab sets @active_tab to all value when tab params is invalid and cookie is invalid' do
-    @controller.stubs(:params).returns({ tab: 'supertab' })
-    @controller.stubs(:cookies).returns({ last_tab: 'woohoo' })
     @controller.set_active_tab
     assert_equal 'all', @controller.instance_variable_get(:@active_tab)
   end