The motivation for this study is the putative link between teaching associations (TAs) and the professionalism of teachers of English as a foreign language (EFL). It has been assumed that TAs lead to professionalism but there is a knowledge gap within the EFL literature because professionalism as a construct has not been adequately conceptualised or operationalised in the few studies of TAs extant. The aim of this study is to investigate the relationship between TAs and professionalism empirically using a robust construct of professionalism. Accordingly, professionalism is operationalised via three interlinking constructs, identity, continuing professional development (CPD) and communities of practice (CoP), and the over-arching research question is: what are stakeholders' perceptions and experiences of the ways in which TAs contribute to the professionalism of EFL teachers? The methodology, qualitative and drawing on a relativist paradigm, is an exploratory case study of the International Association of Teachers of English as a Foreign Language (IATEFL) as the largest UK-based TA. The mono-method is face-to-face interviews (n = 17) conducted with IATEFL officers (n = 4), members (n = 6) and non-members of IATEFL (n = 7). The data are analysed through semi-grounded content analysis with the emergent themes linked to the constructs of identity, CPD and CoP. The strongest and most consistent finding is that TAs are primarily perceived by stakeholders as a vehicle for CPD for EFL teachers. Identity is a much more complex phenomenon and at best the relationship between identity and TAs can be seen as aspirational. It is also found that TAs do supply a sense of community but fail formal criteria to qualify as CoP. The implications are that TAs can impact the professionalism of members and non-members alike through CPD activity but they need to generate much more awareness of their role and function. The original contribution of this study to a neglected area of research within EFL is that it offers a robust conceptualisation of professionalism and includes non-members of TAs in its sample.