The current study tested if proximal transmission of positive and negative affect occurs bidirectionally between mothers and their adolescent children in valence-specific patterns (e.g., maternal positive affect to adolescent positive, but not negative, affect) across a period of 7 minutes and between minutes. Whether adolescent gender moderated transmission effects was also explored. One hundred thirty-5 mothers (29-60 years old) and their children (12-16 years old, 49% female) independently completed questionnaires and then jointly engaged in a naturalistic 7-min problem-solving discussion. Transmission was examined by testing how 1 person's expressed affect (assessed observationally) changed the other person's self-reported state affect across the task. In path analyses, support for bidirectional transmission of negative affect emerged. Transmission was valence-specific, however, evidence for transmission of positive affect was not found. Results also supported cross-valence transmission of negative affect specifically from adolescents to their mothers, such that adolescent expressed negative affect predicted reduced maternal self-reported positive affect. Utilizing cross-lagged path analyses to further examine these findings between minutes revealed that transmission did not occur between specific minutes. Results largely support previous theoretical work on the orthogonal structure of affect and the bidirectionality of parent-adolescent affective interactions. Given this evidence for reciprocal transmission of affect across (not between) minutes in a microsocial context, implications for successful emotion coregulation in parent-adolescent interactions and how these mechanisms may predict long-term outcomes are discussed. (PsycINFO Database Record