The lesson study (LS) model, which originated in Japan, has become popular all over the world. This article will highlight some of the challenges encountered when the LS model was picked up and introduced in a local school context in a Norwegian municipality. The article views this process in the light of research on LS-model transfer into local contexts in various countries, and considers the impact modes of collaboration have on the implementation of a borrowed idea. The aim has been to reflect upon the challenges encountered in transforming a global idea into local practice. A four-stage composite-process model has provided the framework for this personal reflection: stage 1: cross-national attraction; stage 2: decision-making; stage 3: implementation; and stage 4: internalisation. The article argues that the LS model may undergo a transformation from an idea that is global, into a practice that is glocal.