Speckle sensing for motion tracking is described, for example, to track a user's finger or head in an environment to control a graphical user interface, to track a hand-held device, to track digits of a hand for gesture-based control, and to track 3D motion of other objects or parts of objects in a real-world environment. In various examples a stream of images of a speckle pattern from at least one coherent light source illuminating the object, or which is generated by a light source at the object to be tracked, is used to compute an estimate of 3D position of the object. In various examples the estimate is transformed using information about position and/or orientation of the object from another source. In various examples the other source is a time of flight system, a structured light system, a stereo system, a sensor at the object, or other sources.