Understanding under what conditions individuals are willing to support policies aimed at mitigating climate change has important consequences for the legitimacy, costs, effectiveness, and longevity of any policy alternative. Given the politicized nature of climate change, one factor that has been found to be important in explaining public support is partisan political communication. It has, for example, been shown how political communication has important effects on public beliefs and attitudes regarding climate change. A lack of country comparative studies, together with methodological limitations in previous research, has, however, led to a limited understanding of how these processes work, especially in a comparative perspective. In this paper, the effects of political communication on public support for climate mitigation, and the cross-country variations of these effects, is studied. Specifically, this paper investigates: (1) to what degree individual policy attitudes varies across party lines, (2) to what degree variations in policy attitudes can be explained by the effect of party cues, and (3) to what extent the effect of partisanship and political communication varies across political contexts. Using original data from a country comparative online public opinion survey covering Australia, New Zealand, Norway and Sweden political communication is found to significantly influence public policy attitudes in all contexts studied, albeit to different degrees.