diff --git a/.release-please-manifest.json b/.release-please-manifest.json
index 5f02af31..caf5ca3f 100644
--- a/.release-please-manifest.json
+++ b/.release-please-manifest.json
@@ -1,3 +1,3 @@
 {
-  ".": "0.25.1"
+  ".": "0.26.0"
 }
\ No newline at end of file
diff --git a/.stats.yml b/.stats.yml
index 062111e2..48863a6e 100644
--- a/.stats.yml
+++ b/.stats.yml
@@ -1,4 +1,4 @@
 configured_endpoints: 118
-openapi_spec_url: https://storage.googleapis.com/stainless-sdk-openapi-specs/openai%2Fopenai-937fcfac8cbab692796cd9822b37e48a311e2220a8b103106ded0ee92a0b9484.yml
-openapi_spec_hash: 74a0c58b5b8c4e06792d79b685e02a01
+openapi_spec_url: https://storage.googleapis.com/stainless-sdk-openapi-specs/openai%2Fopenai-410219ea680089f02bb55163c673919703f946c3d6ad7ff5d6f607121d5287d5.yml
+openapi_spec_hash: 2b3eee95d3f6796c7a61dfddf694a59a
 config_hash: 666d6bb4b564f0d9d431124b5d1a0665
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 825be603..94c22ce3 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,13 @@
 # Changelog
 
+## 0.26.0 (2025-09-23)
+
+Full Changelog: [v0.25.1...v0.26.0](https://github.com/openai/openai-ruby/compare/v0.25.1...v0.26.0)
+
+### Features
+
+* **api:** gpt-5-codex ([6c9b9b5](https://github.com/openai/openai-ruby/commit/6c9b9b58dabc56fbe9ac871517f837a662c6c237))
+
 ## 0.25.1 (2025-09-22)
 
 Full Changelog: [v0.25.0...v0.25.1](https://github.com/openai/openai-ruby/compare/v0.25.0...v0.25.1)
diff --git a/Gemfile.lock b/Gemfile.lock
index 8cb88419..96026503 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -11,7 +11,7 @@ GIT
 PATH
   remote: .
   specs:
-    openai (0.25.1)
+    openai (0.26.0)
       connection_pool
 
 GEM
diff --git a/README.md b/README.md
index 31135e7e..97b13dbe 100644
--- a/README.md
+++ b/README.md
@@ -15,7 +15,7 @@ To use this gem, install via Bundler by adding the following to your application
 <!-- x-release-please-start-version -->
 
 ```ruby
-gem "openai", "~> 0.25.1"
+gem "openai", "~> 0.26.0"
 ```
 
 <!-- x-release-please-end -->
diff --git a/lib/openai/models/all_models.rb b/lib/openai/models/all_models.rb
index 188ab131..f9a35a24 100644
--- a/lib/openai/models/all_models.rb
+++ b/lib/openai/models/all_models.rb
@@ -24,6 +24,7 @@ module ResponsesOnlyModel
         O4_MINI_DEEP_RESEARCH_2025_06_26 = :"o4-mini-deep-research-2025-06-26"
         COMPUTER_USE_PREVIEW = :"computer-use-preview"
         COMPUTER_USE_PREVIEW_2025_03_11 = :"computer-use-preview-2025-03-11"
+        GPT_5_CODEX = :"gpt-5-codex"
 
         # @!method self.values
         #   @return [Array<Symbol>]
diff --git a/lib/openai/models/responses_model.rb b/lib/openai/models/responses_model.rb
index e86bc725..4f642c88 100644
--- a/lib/openai/models/responses_model.rb
+++ b/lib/openai/models/responses_model.rb
@@ -24,6 +24,7 @@ module ResponsesOnlyModel
         O4_MINI_DEEP_RESEARCH_2025_06_26 = :"o4-mini-deep-research-2025-06-26"
         COMPUTER_USE_PREVIEW = :"computer-use-preview"
         COMPUTER_USE_PREVIEW_2025_03_11 = :"computer-use-preview-2025-03-11"
+        GPT_5_CODEX = :"gpt-5-codex"
 
         # @!method self.values
         #   @return [Array<Symbol>]
diff --git a/lib/openai/version.rb b/lib/openai/version.rb
index 6fb9156b..fa1b7463 100644
--- a/lib/openai/version.rb
+++ b/lib/openai/version.rb
@@ -1,5 +1,5 @@
 # frozen_string_literal: true
 
 module OpenAI
-  VERSION = "0.25.1"
+  VERSION = "0.26.0"
 end
diff --git a/rbi/openai/models/all_models.rbi b/rbi/openai/models/all_models.rbi
index 34231363..5708c46d 100644
--- a/rbi/openai/models/all_models.rbi
+++ b/rbi/openai/models/all_models.rbi
@@ -65,6 +65,11 @@ module OpenAI
             :"computer-use-preview-2025-03-11",
             OpenAI::AllModels::ResponsesOnlyModel::TaggedSymbol
           )
+        GPT_5_CODEX =
+          T.let(
+            :"gpt-5-codex",
+            OpenAI::AllModels::ResponsesOnlyModel::TaggedSymbol
+          )
 
         sig do
           override.returns(
diff --git a/rbi/openai/models/responses_model.rbi b/rbi/openai/models/responses_model.rbi
index b7ec74bf..0527d58f 100644
--- a/rbi/openai/models/responses_model.rbi
+++ b/rbi/openai/models/responses_model.rbi
@@ -73,6 +73,11 @@ module OpenAI
             :"computer-use-preview-2025-03-11",
             OpenAI::ResponsesModel::ResponsesOnlyModel::TaggedSymbol
           )
+        GPT_5_CODEX =
+          T.let(
+            :"gpt-5-codex",
+            OpenAI::ResponsesModel::ResponsesOnlyModel::TaggedSymbol
+          )
 
         sig do
           override.returns(
diff --git a/sig/openai/models/all_models.rbs b/sig/openai/models/all_models.rbs
index 7b1f8e0a..53864a35 100644
--- a/sig/openai/models/all_models.rbs
+++ b/sig/openai/models/all_models.rbs
@@ -19,6 +19,7 @@ module OpenAI
         | :"o4-mini-deep-research-2025-06-26"
         | :"computer-use-preview"
         | :"computer-use-preview-2025-03-11"
+        | :"gpt-5-codex"
 
       module ResponsesOnlyModel
         extend OpenAI::Internal::Type::Enum
@@ -33,6 +34,7 @@ module OpenAI
         O4_MINI_DEEP_RESEARCH_2025_06_26: :"o4-mini-deep-research-2025-06-26"
         COMPUTER_USE_PREVIEW: :"computer-use-preview"
         COMPUTER_USE_PREVIEW_2025_03_11: :"computer-use-preview-2025-03-11"
+        GPT_5_CODEX: :"gpt-5-codex"
 
         def self?.values: -> ::Array[OpenAI::Models::AllModels::responses_only_model]
       end
diff --git a/sig/openai/models/responses_model.rbs b/sig/openai/models/responses_model.rbs
index fb64b13b..839b54c0 100644
--- a/sig/openai/models/responses_model.rbs
+++ b/sig/openai/models/responses_model.rbs
@@ -19,6 +19,7 @@ module OpenAI
         | :"o4-mini-deep-research-2025-06-26"
         | :"computer-use-preview"
         | :"computer-use-preview-2025-03-11"
+        | :"gpt-5-codex"
 
       module ResponsesOnlyModel
         extend OpenAI::Internal::Type::Enum
@@ -33,6 +34,7 @@ module OpenAI
         O4_MINI_DEEP_RESEARCH_2025_06_26: :"o4-mini-deep-research-2025-06-26"
         COMPUTER_USE_PREVIEW: :"computer-use-preview"
         COMPUTER_USE_PREVIEW_2025_03_11: :"computer-use-preview-2025-03-11"
+        GPT_5_CODEX: :"gpt-5-codex"
 
         def self?.values: -> ::Array[OpenAI::Models::ResponsesModel::responses_only_model]
       end