In an era of increased political polarization, it is important to measure how receptive US American citizens are to diverse political views. Being more open to diverse political viewpoints—openness to political pluralism—may involve holding emotional and intellectual tolerance, non-rigidity, and proactive motivation to seek out different political perspectives. In three preregistered studies of US residents, we present a new self-report measure of openness to political pluralism (OPP) consisting of 25 items. In Study 1 (MTurk n = 400), we verified a preregistered bifactor model with four facets, conducted initial validity analyses, and created a short five-item version (OPPS). Both OPP and OPPS have high internal consistency and test-retest reliability. In Studies 2 and 3, MTurk participants (n = 258) and Qualtrics panel participants (n = 296) completed OPP and measures of related constructs to validate our scale. OPP was modestly correlated with actively open-minded thinking (AOT) and highly correlated with open-minded cognition-political (OMC-P). Greater OPP was associated with an inverted U-shape relation to left-right political orientation. It was also correlated with more politically diverse social networks and varied information seeking. We discuss how our measure of openness to political pluralism can be used in future research.