This study involving 463 adolescents examined the impact of parent, teen, and parent–teen interaction processes on spontaneous disclosure to mothers. High openness in communication and stronger disclosure self‐efficacy beliefs were associated with more disclosure at follow‐up. Although a positive relationship was also found for maternal warmth/responsiveness when it was considered together with other parenting attributes, its unique contribution to the disclosure process was attenuated once openness and self‐efficacy beliefs were taken into account. Domain‐specific predictors of disclosure were also explored. Open communication was important for disclosure across all domains, while self‐efficacy beliefs were critical for revealing difficult information. These findings underscore the importance of fostering an open environment in families that nurtures adolescents' confidence to engage in disclosure with parents.