Abstract Affective polarization is little-studied in systems that present ambiguity in relevant political groups. We assess dynamic patterns in intergroup liking and perceived intelligence over 5 waves of a pre-registered survey with 4 panel waves (N ≃ 2,000-3,000) conducted before, during, and after the 2022 Brazilian elections. Given the nature of Brazil’s political system, we document horizontal affective polarization of combinations of political ingroups and outgroups. These include left-right self-placed position-holders, negative partisans, and supporters of the most important presidential candidates, “Lula” and “Bolsonaro”. Categorized by first-round vote intention, the latter grouping (lulistas vs. bolsonaristas) shows particularly intense affective polarization before the election campaign, which remains stable through the elections, thereafter fading approximately symmetrically. We also demonstrate that experimental treatment conditions correcting misperceptions of group stances on single, controversial policies reduce affective polarization by up to 6.66 percentage points (liking thermometer), and, in some instances, also shift policy support.