Constance J. Chang-Hasnain is a Taiwanese-American chemical engineer who is the chairperson and founder of Berxel Photonics Co. Ltd. and Whinnery Professor Emerita of the University of California, Berkeley.

She joined the University of California Berkeley as professor of electrical engineering and computer sciences in 1996.

She was the founding co-director of Tsinghua-Berkeley Shenzhen Institute (TBSI) 2015–2020 and the chief academic officer of Berkeley Education Alliance for Research in Singapore (BEARS) 2015–2018.

She was elected Director-at-Large of the Board of Directors from 1998 to 2000 and served on Optica's Centennial Advisory Panel from 2014 to 2016.

In 2024, she received the IEEE Nick Holonyak Jr. Medal for pioneering contributions to vertical-cavity surface-emitting laser (VCSEL) and VCSEL-based photonics for optical communications and sensing.