Project ThaiPASS (Thai-UK Python+Astronomy Summer School) is a human-capacity building STEM outreach project proposed jointly by the E.A. Milne Centre for Astrophysics (University of Hull, UK) and the Institute of Fundamental Study (Naresuan University, Thailand), with partnership from the National Astronomical Research Institute of Thailand (NARIT). Each ThaiPASS is a full-board summer school aimed at Thai secondary school students age around 16-18. Students will receive training in scientific computing in Python, one of the fastest growing open-source programming languages and one of the most desirable from an employability perspective. Students will learn to use Python to handle data via the medium of astronomy, which is one of the most inspiring and high-impact STEM enablers. Over a 5-day course, professional astronomers from the UK will guide students through a series of lectures and hands-on tasks involving handling astronomical data and producing visual output such as astronomical images and videos. Students will leave the summer school with a new perspective on the role of data science in modern reserach, and will be inspired to continue to learn coding beyond the scope and time-scale of the summer school. The summer school will also include a "university and career" day to inform students on how STEM subjects can be taken further at university level and as a career. The ThaiPASS project will address many of the challenges in science and ICT education in Thailand, which has fallen far behind other countries emerging out of the middle-income trap. At ThaiPASS, we will bring STFC-funded science to new audiences who may not have the opportunity to access such training otherwise. The skills developed at ThaiPASS are current, relevant and easily transferable to a wide range of industrial and academic applications. The UK team from Hull particularly understand the importance of high-quality STEM outreach: Hull is one of the most impoverished cities in the UK with a large proportion of under-performing schools. However, through our previous outreach work (over 150 science outreach events in the past 3 years, mostly in Hull and the Yorkshire region), we have witnessed first-hand the positive transformation STEM education can make for young people who might not have otherwise considered taking up science at University and as a career. In recent years, Thailand has established itself as an emerging player in astrophysics research thanks to a new generation of internationally recognised researchers at NARIT, Naresuan. Chulalongkorn, Suranaree etc. Investment in the ThaiPASS project will be a small but significant step towards forging a strong and lasting Thai-UK synergy, which can easily spin off into future collaborations in astrophysics research and further outreach activities.