In the light of neo-institutional theory, and adopting the case-study research methodology, this paper explains the adoption of IPSASs for modernising public sector accounting in Estonia. This study reveals that the smooth – yet gradual – adoption of IPSASs-compliant accounting systems was enabled by the involvement of powerful actors (i.e. institutional entrepreneurs) with foreign and/or business backgrounds. In addition, the change in public sector accounting in Estonia was facilitated by the developments in its international positioning, characterised by the transition from a Soviet-communist to a market economy and subsequent EU membership, and by the absence of past accounting practices which could potentially hinder the change.