How does opposition local government affect opposition parties’ prospects of replacing authoritarian incumbents? In this chapter, I ask if opposition local government changes how voters think about opposition parties and how likely they are to vote for opposition parties using evidence from Tanzania. I leverage interviews and survey data to show that opposition local government changes voters’ perceptions of opposition parties even if they remain loyal to the ruling party. Comparing voters living under regime and opposition local governments, I find differences in how much voters trust opposition parties, how they view the role of opposition parties in Tanzania and how likely they would be to support an opposition party. I also leverage election data from four electoral cycles to show that opposition local control increases opposition vote at subsequent local and national elections. Furthermore, I show that support for opposition parties and favourable ideas around them diffuse around areas of opposition local control. I take advantage of temporal variation and close elections to demonstrate that these effects are not driven by selection. I contend that these results are driven by the credibility opposition parties build from governing at the local level which allows them to build support and break out of their usual constituencies.