While there is literature on ‘populist securitisation’ and on the ‘securitisation of Islam’, the possibility that some populists may desecuritise Islam is not sufficiently explored. Left-wing populist parties have demonstrated solidarity towards Muslim minorities in Europe through a discourse based on inclusionary rhetoric and deconstruction of the securitising narratives promoted by mainstream and populist right-wing parties. However, their attitude towards Islam can be ambiguous. This paper argues that left-wing populists tend to desecuritise Islam. However, desecuritisation happens in ways that do not always accommodate Muslims’ religious freedoms. This happens because the driver of the left-wing populist desecuritisation of Islam lies in the left-wing thick ideology surrounding populism and not in the populist thin core. I illustrate this argument through the case study of Jean-Luc Mélenchon, leader of the left-wing populist party La France Insoumise. Through a discourse analysis of texts from 2009 to 2022, I show that Mélenchon has predominantly desecuritised Islam. While his desecuritisation is populist, it has not been truly emancipatory for Muslims. Although a more committed fight against Islamophobia has emerged since 2019, Mélenchon’s ideological attachment to laïcité hinders a full rearticulation of French political community based on genuine recognition of Muslims’ religious freedoms.