gpt-oss-20b is an AI model released by OpenAI on Aug 5 2025, 0 days after gpt-oss-120b. It is the 19th tracked release from OpenAI out of 31 total. It is an open-source / open-weight model.
About OpenAI: Creators of ChatGPT and the GPT series of models. Pioneered large-scale language model research.