The history of exclusion and discrimination in American politics makes it difficult for the targeted groups to realize of a sense of political belonging. This creates a barrier to political expression that exacerbates resource-based barriers, like education and income. I draw from theories of stereotype threat and belonging uncertainty in social psychology to introduce a theory of political belonging uncertainty. One important way that political belonging uncertainty manifests is in a preference to know more about a topic before reporting opinions. As a result, opinion surveys underrepresent the opinions of minorities and women. First, using data from nationally representative surveys, I show that, even holding constant education and political knowledge, women, African Americans and Latinx Americans offer fewer opinions than white Americans. I develop a measure of political belonging uncertainty and I show experimentally that political belonging uncertainty contributes to lower expression. I also present results from a survey showing that, when given the option, women and black Americans ask for more information before offering opinions—even when starting from the same level of political knowledge and education as white men. In contrast to activities that require more effort and more time, responding to a political opinion question should be relatively low-effort, and also comparatively private. Thus, I argue that this applies to lower levels of political engagement generally. This paper contributes to literature on non-response to opinion questions and minority political behavior, specifically from a political psychology perspective.