To characterize infant reactions to jealousy evocation, 94 6-month-olds and their mothers were videotaped in an episode where the mothers directed positive attention toward a lifelike doll, and in 2 contrasting interactions: face-to-face play and a still-face perturbation. Cross-context comparisons of affects and behaviors revealed that jealousy evocation responses were distinguished by diminished joy and heightened anger and intensity of negative emotionality, comparable to levels displayed during the still-face episode; heightened sadness, with durations exceeding those displayed during still-face exposure; and an approach response consisting of interest, looks at mother, and diminished distancing, which was more pronounced than that demonstrated during play. Infants' heightened anger and sadness during jealousy evocation correlated with heightened maternal sensitivity and dyadic vocal turn-taking, respectively, during play; and infants' diminished joy and interest during jealousy evocation were associated with heightened maternal withdrawal and intrusiveness, respectively, during play. Both fear and mother-directed gaze were greater in girls. The discussion argues for interpreting the infant's mixed and agitated reaction to jealousy evocation as evidence of jealousy. (Contains 4 tables and 1 figure.)