Ontario Science Centre (OSC) (or in French: Centre des sciences de l'Ontario) is a science museum in Toronto, Ontario, Canada, near the Don Valley Parkway about 11 kilometres (6.8 mi) northeast of downtown on Don Mills Road just south of Eglinton Avenue East. It is built down the side of a wooded ravine formed by one branch of the Don River. The innovative design, consisting of three main buildings connected by a series of bridges and escalators, follows the natural contours of the Don River ravine, into which the Centre descends.
The Centre has several hundred interactive and passive exhibits throughout the buildings. They feature everything in science and nature. They feature geology, the science of nature (in the west wing), astronomical science, how to play music and technology in the south wing, human anatomy, communication and bias, and some miscellaneous artifacts of science. The astronomical wing features Toronto's only operating planetarium, as well as one of the few Mars and Moon rocks on public display in Canada.