We investigate the properties of the B-band Tully-Fisher (TF) relation for 25 compact group galaxies, using Vmax derived from 2-D velocity maps. Our main result is that the majority of the Hickson Compact Group (HCG) galaxies lie on the TF relation, although with large scatter. However, 20% of the galaxies, including the lowest-mass systems, seem to have higher B luminosities, for a given mass, or alternatively, a mass which is too low for their luminosities. We favour the scenario of brightening of the outliers due to either enhanced star formation or merging, rather than truncation of the dark halo due to interactions, to explain the position of the outliers on the TF relation.