For more than a century, many practitioners and researchers have argued that municipal politicians are more ideologically moderate – that is, closer to the centre of a unidimensional left-right ideological scale – than their national counterparts. Testing this claim requires direct comparison of politicians who represent similar constituents but who are elected at different levels of government, but comparative data of this sort are rarely available. Here, I use new data from surveys of Canadian municipal, provincial, and federal politicians to rigorously test the “municipal moderation” thesis. Comparing politicians' symbolic ideological self-understandings N≈3,000 and their latent policy ideologies N≈775, I find strong evidence that municipal politicians think of themselves as more ideologically moderate, but are not more moderate in their policy beliefs. Further, I leverage variation in the partisan identities of Canadian municipal politicians to show that differences in ideological moderation across levels of government disappear when we remove municipal non-partisans from the analysis. My results reinforce the view that municipal politicians hold non-ideological cultural norms but are embedded in an ideological electoral and policymaking context. My analysis also illustrates the analytical potential for “vertical” rather than “horizontal” comparative research designs.