Lilian Weng
Lilian Weng is an artificial intelligence researcher and author of the technical blog Lil’Log who served as OpenAI’s vice president of research and safety and co-founded Thinking Machines LabThinking Machines LabThinking Machines Lab is an artificial intelligence research and product company founded by former OpenAI chief technology officer Mira Murati and several former OpenAI researchers, with the aim of making AI systems more understandable, customizable and collaborative. In July 2025 it closed a $2 billion seed round at a $12 billion valuation; its main product is Tinker, an API that lets researchers and developers fine-tune open-weight models, and since 2026 it has also released the open-weights Inkling model family.Open the full entry, before returning to OpenAI in July 2026 to lead a team accelerating its internal research.
Contents7 sections
Key facts
June 2017Starting Lil’Log
The earliest post in the archive of her technical blog Lil’Log is dated June 21, 2017, an overview of deep learning for newcomers; later well-known posts include “Attention? Attention!” in 2018 and “LLM Powered Autonomous Agents” in June 2023. In the blog’s FAQ she says she periodically updates older posts.[1][2]
2018–2024At OpenAI
According to AI Magazine, she holds a BA in information systems and computer science from Peking University and a PhD from Indiana University Bloomington, worked at Facebook and Dropbox, and was at OpenAI from February 2018.[3]
TechCrunch reported that after joining OpenAI she first worked on the robotics team, which built a robot hand that could solve a Rubik’s Cube; in 2021 she moved to help build the applied AI research team, in 2023 she was tasked with creating a dedicated safety systems team, and from August 2024 she served as vice president of research and safety.[4]
November 2024Announcing Her Departure from OpenAI
On November 8, 2024, she announced on X that she was leaving OpenAI after seven years, saying she wanted to reset and explore something new, with November 15 as her last day.[4]
February 2025Co-Founding Thinking Machines Lab
On February 18, 2025, Mira Murati publicly unveiled the artificial intelligence research and product company Thinking Machines Lab, and Fortune’s report on its initial team listed her as a former OpenAI vice president; TechCrunch and other outlets later described her as a co-founder of the company.[5][6][7]
July 2026Leaving Thinking Machines Lab and Returning to OpenAI
In late July 2026, she announced in an internal message, also shared on X, that she was stepping down from her role at Thinking Machines Lab. On July 29, OpenAI confirmed to TechCrunch that she was rejoining the company to lead a top-level team focused on accelerating its internal research, which will support cross-team work on recursive self-improvement.[6][3]
Related Organizations, Websites, and Public Accounts
OpenAI: Official website: https://openai.com/ (opens in a new window)[4]
Thinking Machines Lab: Official website: https://thinkingmachines.ai/ (opens in a new window)[7]
Personal website: Public link: https://lilianweng.github.io/ (opens in a new window)[2]
X: Public account: https://x.com/lilianweng (opens in a new window)[2]
Sources
- Archive | Lil'Log (opens in a new window)
- FAQ | Lil'Log (opens in a new window)
- People Moves: Lilian Weng, OpenAI (opens in a new window)
- OpenAI loses another lead safety researcher, Lilian Weng (opens in a new window)
- Former OpenAI CTO Mira Murati finally unveils her Thinking Machines Lab startup and a leadership team stacked with former OpenAI colleagues (opens in a new window)
- Thinking Machines co-founder Lilian Weng left the company, then joined OpenAI (opens in a new window)
- Thinking Machines Lab (opens in a new window)