This study applied phenomenology as a methodology in order to gain deeper insights into the lived professional development (PD) experiences of Vietnamese tertiary English as a foreign language (EFL) lecturers. Evidence from this study highlights that lecturers’ PD is a multidimensional and dynamic activity. Grounded in a combination of ecological systems theory and andragogy theory, the findings of this study led to the design of an integrated framework of effective PD for tertiary EFL lecturers that incorporates the three main dimensions of content, context and process. This representation helps to shed light on what PD planners and academic managers need to focus on when organising and implementing PD activities. The study contributes to the current literature related to tertiary EFL lecturers’ lived experiences of PD within the Vietnamese higher education context and may be applied to other international contexts.