This paper focuses on issues concerning in-service English as an additional language or dialect teachers' views on professional development (PD) in an online environment. On the basis of the data collected via a questionnaire survey and a series of interviews, this study finds that intrinsic and extrinsic incentives compel or impede teachers participating in PD and that the trajectories of their PD are shaped by the complex operations of the incentives and the equilibrium among the factors involved. The findings of the study also show that teachers are more interested in improving professional practice and that they prefer an online PD programme which includes both synchronous interactions and asynchronous digitalised visual and written resources online. It also discusses implications of this study for teachers, teacher educators and trainers, and PD programme designers and providers.