This article introduces the distinction between thin and thick contracts to the investigation of licensing-in as a mechanism for technological learning. Thick contracts include a clause specifying that the licensors are obligated to assist the licensees in assimilating and integrating the technology. Drawing on a sample of 133 licensees and an equal number of matched nonlicensees, we present empirical evidence that thick contracts propel the licensees' likelihood of introducing new inventions. It is also found that thick contracts act as a substitute for licensees' absorptive capacity. Licensees that are more familiar with the licensed technology are in less need of assistance from the licensors to assimilate and integrate the knowledge. However, this substitution effect is neutralized once the hurdle of invention has been overcome, meaning that the licensees have succeeded to ignite the invention process, suggesting the exploitation of the learning curve, triggered by their mutual understanding.