Sangeeta Thapa established the Siddhartha Art Gallery in 1987. She served on the board of the Patan Museum and is a fellow of the De Vos Institute of Arts Management. In 2009, she launched the Kathmandu International Arts Festival (KIAF) as a triannual event that later transitioned into the Kathmandu Triennale. In 2011, Thapa set up the Siddhartha Arts Foundation as a nonprofit organization to manage KIAF and train the next generation of arts managers and leaders. In 2022, Siddhartha Arts Foundation served as co-commissioner of Nepal’s first pavilion at the Venice Biennale. The President of Nepal awarded Thapa the Jana Sewa Prabal medal for her contributions to the field of Nepalese art.