This study investigates the public sector external auditing (PSA) phenomenon in Tanzania, and seeks to understand the role of PSA, and the conditions in which it operates. In recent years, Tanzania has shown increased recognition of the contribution PSA makes to accountability, performance and the fight against corruption (CAGT, 2007). While empirical evidence to support this recognition is lacking in Tanzania, the literature review revealed mixed findings. Furthermore, the study responds to calls for more PSA studies in developing countries (Goddard, 2010) in general (Leung, White and Cooper, 2011) and those which adopt critical interpretive approaches (Baker and Bettner, 1997). The study adopts and implements a critical interpretive research strategy in fieldwork undertaken at the National Audit Office of Tanzania (NAOT). Specifically, it employs the grounded theory method (GTM) as an interpretive approach and strategically accommodates critical thinking in questioning and interpreting the case under study (Laughlin, 1995; Gibson, 2007). It also adopts elements of Habermas’ critical theory (HCT) as a lens through which interpretively field gained understanding is extended (Habermas, 1987). This study’s findings indicate that PSA in Tanzania encountered colonising tendencies because of weak working relationship between the NAOT and other accountability agencies, inconsistencies in governance and politics, the culture of corruption and secrecy, dependence on foreign financing and mimicking of foreign models. To coexist within this colonising environment, managing colonising tendencies appeared to be the core strategy for both the government and external auditors. While the government appeared to manage NAOT appearance and exploited the legitimising features of PSA, external auditors manoeuvred within colonising tendencies and attempted to maintain the ‘audit supremacy’ image. External auditors managed their relationship with auditees and the complexities of PSA roles. Managing colonising tendencies resulted into obscured subordination of PSA, contributing to cosmetic accountability and growing public interest in PSA. This research contributes to the understanding of the role and conditions shaping PSA in a developing country. It provides field-based evidence that maintaining an appearance of SAI’s ‘supremacy’ without resolving problems in the underlying power relations leads to superficial contributions from PSA. It also contributes to critical interpretive research in developing countries. Exploiting the pragmatic nature of grounded theory (GT), the research provides a practical demonstration of accommodating critical theory in a GTM. Finally, the colonisation thesis in HCT helped the researcher to develop a societal extension of the emergent theory, which also extended the thesis by highlighting external auditors’ responses to colonisation<br/