We explore the role of partisanship in policy diffusion. Previous studies suggest that partisanship may influence the willingness of public officials to learn from the experience of their peers. Officials’ willingness to consider policies endorsed by copartisans can arise either because party labels are used as informational cues or simply due to copartisan imitation. In the latter case, knowing more about the policy trade-offs should have no effects on politicians’ preferences. Based on two experiments with local public officials where both the party endorsing a policy and the type of information provided were manipulated, we find consistent partisan bias. When a policy is endorsed by copartisans, public officials are more likely to consider pursuing it, and additional policy information does not mitigate this bias. Exploratory analyses of the information-seeking behavior of officials suggest that the partisan bias is not due to differential exposure or attention to policy trade-offs.