diff --git a/rb/lib/selenium/webdriver/common/options.rb b/rb/lib/selenium/webdriver/common/options.rb
index bddb91063737b..997aced69ec5d 100644
--- a/rb/lib/selenium/webdriver/common/options.rb
+++ b/rb/lib/selenium/webdriver/common/options.rb
@@ -131,11 +131,20 @@ def w3c?(key)
 
       def process_w3c_options(options)
         w3c_options = options.select { |key, val| w3c?(key) && !val.nil? }
-        w3c_options[:unhandled_prompt_behavior] &&= w3c_options[:unhandled_prompt_behavior]&.to_s&.tr('_', ' ')
+        w3c_options[:unhandled_prompt_behavior] &&=
+          process_unhandled_prompt_behavior_value(w3c_options[:unhandled_prompt_behavior])
         options.delete_if { |key, _val| w3c?(key) }
         w3c_options
       end
 
+      def process_unhandled_prompt_behavior_value(value)
+        if value.is_a?(Hash)
+          value.transform_values { |v| process_unhandled_prompt_behavior_value(v) }
+        else
+          value&.to_s&.tr('_', ' ')
+        end
+      end
+
       def process_browser_options(_browser_options)
         nil
       end
diff --git a/rb/spec/unit/selenium/webdriver/chrome/options_spec.rb b/rb/spec/unit/selenium/webdriver/chrome/options_spec.rb
index 5061aae7cc7ec..96a739ea9611b 100644
--- a/rb/spec/unit/selenium/webdriver/chrome/options_spec.rb
+++ b/rb/spec/unit/selenium/webdriver/chrome/options_spec.rb
@@ -267,6 +267,26 @@ module Chrome
                                          {'args' => ["--user-data-dir=#{directory}"]})
           end
 
+          it 'processes unhandled_prompt_behavior hash values' do
+            opts = described_class.new(unhandled_prompt_behavior: {
+                                         alert: :accept_and_notify,
+                                         confirm: 'dismiss_and_notify',
+                                         prompt: :ignore,
+                                         before_unload: 'accept',
+                                         default: :dismiss
+                                       })
+
+            expect(opts.as_json).to eq('browserName' => 'chrome',
+                                       'unhandledPromptBehavior' => {
+                                         'alert' => 'accept and notify',
+                                         'confirm' => 'dismiss and notify',
+                                         'prompt' => 'ignore',
+                                         'beforeUnload' => 'accept',
+                                         'default' => 'dismiss'
+                                       },
+                                       'goog:chromeOptions' => {})
+          end
+
           it 'returns a JSON hash' do
             allow(File).to receive(:file?).and_return(true)
             allow_any_instance_of(described_class)