Background: Parental disclosure is a phenomenon that occurs in families to a greater or lesser extent and has different effects on children and family relationships. Some parents do not know what topics are appropriate for disclosure and what the consequences may be. Therefore, the objective of the present study was to investigate the phenomenology of Iranian mothers› disclosure, its topics, and the experienced consequences. Methods: In this qualitative study based on the descriptive phenomenological method, semi-structured interviews were conducted with a purposive sample of 22 first-marriage mothers who had disclosure experience and at least one 10- to 30-year-old child. The data were analyzed using Colaizzi’s phenomenological method. Results: Analysis of data revealed five main themes and 12 subthemes, including inappropriate disclosure topics (personal problems, problems with spouse), appropriate topics (positive or neutral comments about the spouse, financial problems, neutral and pleasant experiences, goals and viewpoints), contextual topics (negative comments about herself, communication problems with others, unpleasant experiences), positive consequences of disclosure (raising children’s awareness, improving the parent-child relationship quality), and negative consequences (undermining the parent-child relationship quality, creating negative emotions and thoughts in children). Mothers disclosed more frequently and about more diverse subjects to their children than their husbands. Conclusion: In general, the effects of mothers’ disclosure on children are different and depend on its content, and these effects are greater on adolescents. Family therapists, parent educators, and others who work with families can help mothers carefully evaluate their disclosures to establish clear and healthy communication boundaries with their children.