diff --git a/lib/tokenizer/open_ai_gpt4o_tokenizer.rb b/lib/tokenizer/open_ai_gpt4o_tokenizer.rb
new file mode 100644
index 00000000..bf7a28be
--- /dev/null
+++ b/lib/tokenizer/open_ai_gpt4o_tokenizer.rb
@@ -0,0 +1,13 @@
+# frozen_string_literal: true
+
+module DiscourseAi
+  module Tokenizer
+    class OpenAiGpt4oTokenizer < OpenAiTokenizer
+      class << self
+        def tokenizer
+          @@tokenizer ||= Tiktoken.get_encoding("o200k_base")
+        end
+      end
+    end
+  end
+end
diff --git a/plugin.rb b/plugin.rb
index 1b5ad2f9..74718993 100644
--- a/plugin.rb
+++ b/plugin.rb
@@ -9,7 +9,7 @@
 # required_version: 2.7.0
 
 gem "tokenizers", "0.4.4"
-gem "tiktoken_ruby", "0.0.7"
+gem "tiktoken_ruby", "0.0.9"
 
 enabled_site_setting :discourse_ai_enabled
 
diff --git a/spec/shared/tokenizer_spec.rb b/spec/shared/tokenizer_spec.rb
index e46b6d9c..92751624 100644
--- a/spec/shared/tokenizer_spec.rb
+++ b/spec/shared/tokenizer_spec.rb
@@ -109,6 +109,16 @@ describe DiscourseAi::Tokenizer::OpenAiTokenizer do
   end
 end
 
+describe DiscourseAi::Tokenizer::OpenAiGpt4oTokenizer do
+  describe "#size" do
+    describe "returns a token count" do
+      it "for a sentence with punctuation and capitalization and numbers" do
+        expect(described_class.size("Hello, World! 123")).to eq(6)
+      end
+    end
+  end
+end
+
 describe DiscourseAi::Tokenizer::AllMpnetBaseV2Tokenizer do
   describe "#size" do
     describe "returns a token count" do