Timaeus is a lunar impact crater in the northern part of the Moon, on the north edge of Mare Frigoris.

The rim of Timaeus is somewhat pentagonal in shape, with rounded corners.

There is a central rise in the midpoint of the crater floor.

The irregular terrain to the west of Timaeus displays a degree of streaky parallelism, as was noted by the Rev.

Timaeus is a crater of Upper (Late) Imbrian age.