Jaw-Shen Tsai (Chinese: 蔡兆申 Tsai Jaw-Shen, born February 8, 1952 in Taipei, Taiwan) is a Taiwanese physicist. He is a professor at the Tokyo University of Science and a team leader of the Superconducting Quantum Simulation Research Team at the (CEMS) within RIKEN. He has contributed to the area of condensed matter physics in both its fundamental physical aspects and its technological applications. He has recently been working on experiments connected to quantum coherence in Josephson systems. In February 2014, he retired from NEC Corporation, after 31 years of employment. He is a fellow of the American Physical Society as well as the Japan Society of Applied Physics.