Cross-situational continuity and change in anxious solitary girls' behavior and peer relations were examined in interactions with familiar versus unfamiliar playmates. Fourth-grade girls (N=209, M age 9.77 years, half African American, half European American) were identified as anxious solitary or behaviorally normative using observed and teacher-reported behavior among classmates. Subsequently, girls participated in 1-hr play groups containing 5 same-race familiar or unfamiliar girls for 5 consecutive days. Results support both cross-situational continuity and change in anxious solitary girls' behavior and peer relations. Although anxious solitary girls exhibited difficulty interacting with both familiar and unfamiliar playmates relative to behaviorally normative girls, elements of their behavior improved in unfamiliar play groups, a context in which they received less peer mistreatment.