<p>The primary objective of this study was to examine the associations of children's involvement in decisions about research participation with their perceptions of the decision-making process and self-efficacy. Participants were children (ages 8-17) who enrolled in research studies in the prior 2 months. Children completed a questionnaire that yielded three decision-making involvement subscales: Researcher Engages Child, Researcher Supports Autonomy, and Child Participates. Children reported on fairness of the decision-making process and health-related decision self-efficacy. After adjusting for age, higher scores on Researcher Engages Child were associated with greater self-efficacy, and higher scores on Researcher Supports Autonomy were associated with greater perceived fairness. These data underscore the potential importance of researcher-child interactions about research participation when assent is sought, including proactively involving children in the decision by asking for their opinions and communicating their central role in the decision, which are likely to be more meaningful to children than receiving information or signing a form.</p>