Social exclusion is a hurtful experience that can lead to detrimental effects in the social, cognitive, and physiological domains. These consequences can lead to poor, potentially long-lasting, negative outcomes for children. Therefore, it is critical for excluded children to reduce the impact of its negative effects. One helpful strategy to accomplish this is to select social partners who are likely to be inclusive. The current dissertation investigates cognitive processes that may underly children’s partner choice, including the abilities to detect, track, and evaluate social excluders. In Experiment 1, 4-year-old children (n = 32) experienced direct inclusion and exclusion before evaluating target characters. Surprisingly, children in the overall sample did not evaluate excluders more negatively than includers. Experiment 2 further investigated children’s abilities to track and evaluate social excluders using several methodological improvements and a wider age range, including 4- to 6-year-olds (n = 96). With age, children in the overall sample detected social exclusion more often but did not evaluate excluders more negatively. Children who accurately identified includers (n = 68) also evaluated them more positively than excluders. Experiment 3 investigated whether 3- to 6-year-old children who observed third-party games could detect and evaluate social excluders. While children detected and evaluated social excluders, only older children preferred to play with includers. Overall, this work suggests that young children who detect exclusion also evaluate social excluders negatively, although these evaluations may not influence play partner choices until later in development.