Despite recent attention on IT-enabled inclusiveness and transparency in organisational strategy-making (so-called ‘open strategy’), the effectiveness of these principles has not been empirically studied. The specific impact of using information technologies (IT), in addition to pertinent cultural dimensions of firms, on effective strategy-making remains unexplored. Such research gaps are even more prominent when we consider distinct benefits and drawbacks, which we can consider as being outcomes, of an open strategy approach in the extant literature. This study uses a case-based, macro-level approach to explore this outlined lacuna. Data on different degrees of openness, use of IT in strategy-making, and the existence of an open culture in cases of strategy have been analysed in this study using a set-theoretic approach and fsQCA technique. The findings show that inclusiveness in strategy-making and use of IT have a central role in the effectiveness of strategy in firms. In addition, we find transparency to be a core condition in strategy-making and its absence leads to the likely failure of strategy. The paper discusses these contributions against the existing literature on open strategy and explicates potential implications of the study for both practice and research."