This article uses an ecological approach to predict students' peer acceptance within junior high school classes. The authors investigate whether various characteristics (self-perception of physical attractiveness and athletic competence, cognitive ability, agreeableness, extraversion, age, parents education, number of siblings, siblings at same school, parental control, percentage of classmates who attended the same primary school, ethnicity) predict peer acceptance and whether effects are consistent across classes. Participants are 6,847 students ([plus or minus] 13 years) from 461 classes in the Netherlands. Girls' and boys' data are analyzed separately using multilevel analyses. Extraversion and the percentage of classmates from the same primary school are the strongest predictors of peer acceptance for boys and girls. Smaller effects are observed for self-perception of athletic competence (boys and girls), agreeableness (girls), and ethnicity (boys). The effects are consistent across classes. The need for more complex models of peer acceptance is discussed. (Contains 7 tables and 8 endnotes.)