Objective: To systematically search for research about the effectiveness of mandatory reporting of child maltreatment and to synthesize qualitative research that explores mandated reporters’ (MRs) experiences with reporting. Design: As no studies assessing the effectiveness of mandatory reporting were retrieved from our systematic search, we conducted a meta-synthesis of retrieved qualitative research. Searches in Medline (OVID), Embase, PsycINFO, CINAHL, Sociological Abstracts, ERIC, Criminal Justice Abstracts, and Cochrane Library yielded over 6000 citations, which were deduplicated and then screened by two independent reviewers. English-language, primary qualitative studies that investigated MRs’ experiences with reporting of child maltreatment were included. Critical appraisal involved a modified checklist from the Critical Appraisal Skills Programme (CASP) and qualitative meta-synthesis was used to combine results from the primary studies. Setting: All healthcare and social-service settings implicated by mandatory reporting laws were included. Included studies crossed nine high-income countries (United States, Australia, Sweden, Taiwan, Canada, Norway, Finland, Israel and Cyprus) and three middle-income countries (South Africa, Brazil, and El Salvador). Participants: The studies represent the views of 1088 MRs. Outcomes: Factors that influence MRs’ decision to report and MRs’ views towards and experiences with mandatory reporting of child maltreatment. Results: Forty-four articles reporting 42 studies were included. Findings indicate that MRs struggle to identify and respond to less overt forms of child maltreatment. While some articles (14%) described positive experiences MRs had with the reporting process, negative experiences were reported in 73% of articles and included accounts of harm to therapeutic relationships and child death following removal from their family of origin. Conclusions: The findings of this meta-synthesis suggest that there are many potentially harmful experiences associated with mandatory reporting and that research on the effectiveness of this process is urgently needed.