Power-sharing institutions, including coalition governments, are widely assumed to make democratization more viable and resorting to violence less likely in societies that are prone to developing conflicts because of ethnic, religious, or ideological divides. However, the theoretical discussions of the circumstances that could help prevent coalitions governments from disintegrating during democratization are scarce. To further our understanding of coalition maintenance during democratization, this paper investigates the only two Arab coalition governments springing from domestic efforts at democratization, the Tunisian Troika (2011–2014) and the Yemeni Coalition Government (1993–1994). Both coalitions were tripartite governments comprising political parties whose ideological and policy preferences were not easily reconciled. Yet while the former facilitated Tunisia’s democratization, the latter’s disintegration contributed to the 1994 war and Yemen’s authoritarian backsliding. This paper asks why the coalition government lasted in Tunisia, and not in Yemen. Drawing on the literatures on power-sharing, opposition alliances, and transitions, it detects three sets of actor-centered considerations which travel safely to democratization contexts and appear highly relevant for understanding coalition dynamics in Yemen and Tunisia: the intra-elite relations, the power balance within the coalition, and the motivations that drive partners to coalesce. Building on a variety of sources including primary documents, original interviews with and memoirs by key Tunisian and Yemeni actors, the paper explores the role of these factors for coalition maintenance. It finds that both coalitions’ internal functioning was strained by adverse power configurations and ideological differences. In Yemen, intra-elite relations were further impaired by mutual distrust. Crucially, a history of sustained partnership along with a normative commitment to the idea of power sharing, existent in Tunisia and not in Yemen, explains the Troika’s maintenance and the break-up of its Yemeni counterpart. While these findings corroborate the benefits of coalition governments for democratization and conflict aversion as proposed in the literature, the paper also cautions against assuming an automatic link between coalition maintenance or cancelation and democratic progress.