OpenAI releases gpt-oss, its first open-weight LLMs since GPT-2
OpenAI released gpt-oss-120b and gpt-oss-20b, open-weight reasoning models under Apache 2.0; the larger one approached o4-mini on core reasoning benchmarks and ran on a single 80GB GPU.
Key facts
- Released 5 August 2025
- gpt-oss-120b and gpt-oss-20b, mixture-of-experts
- Apache 2.0 license
- 120b runs on a single 80GB GPU (near-parity with o4-mini on core reasoning, per OpenAI); 20b on devices with 16GB memory
- Active parameters per token: 5.1B (120b) and 3.6B (20b)
- First OpenAI open-weight language models since GPT-2 (2019)
What happened
OpenAI returned to releasing open weights, partly in response to the rise of Chinese open models.
Why it matters
Gave the US a competitive open-weight reasoning model and ended OpenAI's six-year hiatus from open releases.
Changelog
- 2026-09-29: created
Related events
- OpenAI announces GPT-2 and withholds the full model over misuse concerns ★★★★
- DeepSeek-R1: open-weights reasoning model rivals o1 and shakes markets ★★★★★
Sources (2)
id: 2025-08-05-gpt-oss · updated 2026-09-29 · open in the interactive timeline