In-situ X-ray topography has been used to provide the first clear demonstration of slip transmission through a grain boundary in hexagonal ice. Although the ice was deformed under creep conditions, the relative orientation of the grains and the orientation of the grain boundary with respect to the loading direction discouraged grain boundary sliding and, thus, suppressed dislocation nucleation at the grain boundary. This particular geometrical arrangement is rarely encountered, suggesting that slip transmission through grain boundaries in ice is a rare event.