Why did land reforms attempted in 1936, 1961 and 1994 not lead to more equality, stability, and peace in Colombia? Using a theoretical framework informed by Gramscis theory of passive revolution, this study examines the origin of inequality and the propagation of conflict in Colombia by exploring the relationship between international political economy, production relations and class conflict surrounding three cases of land reform (1936, 1961 and 1994). I argue that land reforms have failed to address inequality and have exacerbated class conflicts for three interrelated reasons: 1) though campesinos demanded the redistribution of large estates, pro-capitalist land reforms left productive plantations intact and instead promoted access to lands in frontier areas where the state had little effective control over property rights; 2) demands for reforms emerged during 'commodity booms', when a bourgeois-peasant alliance in favour of capitalist expansion was possible, but during phases of subsequent crisis and price collapse, agrarian reforms were coopted by landlord-bourgeois alliances that pushed the consolidation of larger, more productive holdings; 3) the failure of reforms to address popular demands for land contributed to an atmosphere of instability in which reactionary elites used popular unrest as a pretext for repression against opponents of capitalism with the support of international financial and military power. The result has been the intensification of land conflicts and several waves of landlord-led dispossession, popular resistance, and counterinsurgency in the 1940s-50s, 1960s-1970s and 1980s-2000s. Political instability in Colombia is indicative of the dynamics of passive revolution as the case lends itself to a Gramscian analysis of uneven development in the 20th century Latin American context. Colombia's experience shows the limits of "passive revolutionary" land reforms which may unite diverse constituencies under certain conditions, but which leave the material and social foundations of conflict fundamentally unchanged, leaving campesinos vulnerable to shifts in global market conditions. This leads me to the conclusion that there will be no stable peace in Colombia without redistributive land reform. Redistribution has been the demand of the agrarian social movement since the 1930s but has been consistently denied in land reforms during broader processes of passive revolution that favour large-scale corporate farming, natural resource development and the debasement and exploitation of labour through dispossession in a context of unevenly expanding capitalism.