This paper uses the concept of teaching and learning regimes (TLRs) to help explore a set of questions about why some academic staff in universities thrive on and benefit from accredited programmes designed to improve HE learning and teaching practices ("educational development programmes") whilst others experience periods of resistance or some drop out altogether. "TLR" is a shorthand term for a constellation of rules, assumptions, practices and relationships related to teaching and learning issues in higher education. These include aspects of the following salient to teaching and learning, each of which we elaborate and illustrate in the paper: identities in interaction, power relations, codes of signification, tacit assumptions, rules of appropriateness, recurrent practices, discursive repertoires, implicit theories of learning and of teaching. The argument presented here is that academic staff on educational development programmes ("participants") bring to programmes sets of assumptions and practices rooted in TLRs. Educational development programmes themselves instantiate TLRs which may be more, or less, compatible with those of individual participants. Where there are incongruities between the two they need not be fatal if participants are able to, or are encouraged to, surface and reflect on previously tacit assumptions embedded in their TLRs. Similarly, there may not be a problem if participants are able to exercise discretion over the application of aspects of different regimes; applying them in different contexts as appropriate. Evidence from participants' writing, participant observation, secondary sources and data from eight interviews inform the paper and form the basis for illustrative vignettes.