Integrated Science Instrument Module (ISIM) is a component of the James Webb Space Telescope, a large international infrared space telescope launched on . ISIM is the heart of the JWST, and holds the main science payload which includes four science instruments and the fine guidance sensor.

ISIM is the spacecraft chassis and instruments that take the light from the main mirror and convert that into the science data that is then sent back to Earth. The other two major sections