Organisational effectiveness (OE) has been a major focus of attention of both organisational theorists and practitioners for many decades; however, its definition remains contested and there is little consensus as to how it should be evaluated. A number of researchers have proposed that definitions of OE are dependent upon theoretical perspectives, as well as individual perceptions of different stakeholders. In Thailand, the influence and role of stakeholder perceptions on OE have yet to be identified and understood, both in the public and private sectors. The focus of the study is to analyse how OE is viewed by stakeholders both idealistically and realistically, and more importantly, how such views are aligned between these stakeholders. In this research, the organisations in question are quasi-autonomous public sector organisations (QAPSOs) which represent a relatively recent form of government institutions in Thailand and have been granted considerable autonomy. In addition, these organisations' conception has been heavily influenced by New Public Management (NPM) principle. A qualitative method with sixty-three semi-structured interviews was employed to accumulate primary data. The findings confirm the influence of NPM on organisational and managerial form, culture, and OE, of QAPSOs; however, the perceptions among stakeholders seemed to be unaligned to each other because of information asymmetry, individual focus and preferences, and individual experience. It is suggested that, in order to fill those gaps, the government should be aware of current obstacles and exercises more effort in finding solutions through, for instance, more communication and active participation among all related parties. This research has addressed gaps by providing empirical evidence regarding the notion of OE concept in the context of the public sector in Asian countries and applying stakeholder theory as a theoretical framework to explain the perception of OE in the autonomous public organisations in countries which have been influenced by NPM. The findings have the potential to raise policymakers' awareness of the importance of communication strategies in delivering the right message to all targeted parties without misinterpretation, as well as emphasising the importance of governance structures of autonomous organisations.