Galaxy-galaxy lensing (GGL) measures the 2-point cross-correlation between galaxies and mass in the universe. In this work we seek to generalise this effect by considering the third-order correlations between galaxies and mass: galaxy-galaxy-galaxy lensing. We introduce the higher-order cross-correlation functions and discuss their physical interpretation in terms of the halo model. We then demonstrate that measuring the lensing shear of background galaxies about foreground galaxy pairs, which we term galaxy-galaxy-galaxy lensing, provides a measure of the third-order cross functions. We note that current surveys in which detections of the cosmic shear 3-point correlation function have been reported should also be able to detect galaxy-galaxy-galaxy lensing. Indeed, we suggest that this effect may already have been detected in recent studies of GGL.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html