Professional learning communities (PLCs) have been recognised as having the potential to raise the quality of teachers, teaching and student learning through structured teacher collaboration, and have been featured prominently in Singapore and Shanghai--both considered top-performing Asian societies in the Program for International Student Assessment (PISA). Although embedded in education systems that are considered centralised, there are still significant differences. Drawing out key implications from the experiences of Singapore and Shanghai, this paper highlights the potential challenges in implementing PLCs. These challenges include heavy teacher workload, ambiguities in the understanding and implementation of PLCs, and hierarchical work structures. The discussions emanating from the comparison between Singapore and Shanghai PLCs seek to contribute towards the international literature on fostering teacher collaboration through PLCs, which has been predominantly Western-centric.