This article examines the effect of membership in farmer groups (MFG) on the adoption lag of agricultural technologies and farm performance in the Democratic Republic of Congo, Burundi and Rwanda. We use duration and stochastic production frontier models on farm household data. We find that long period of MFG reduces adoption lag and much more so if combined with sustainable extension service delivery from government or development agencies. Farmer groups function as an important mechanism for improving farm productivity through reduced technical inefficiency in input use. We discuss the policy implications under which farmer groups are a useful channel to reduce adoption lag, and by what means improved farm performance can be achieved.