Although several interventions aimed to promote end-of-life conversations are available, it is unclear whether and how these affect delivery of end-of-life conversations. Measuring the processes associated with high-quality end-of-life care may trigger improvement. To estimate the effect of interventions aimed to promote end-of-life conversations in clinical encounters with patients with advanced chronic or terminal illness or their family, on process indicators of end-of-life conversations. Systematic review with meta-analysis (PROSPERO no. CRD42021289471). Four databases (PubMed, CINAHL, PsycINFO, and Scopus) were searched up to September 30, 2021. The primary outcomes were any process indicators of end-of-life conversations. Results of pairwise meta-analyses were presented as Risk Ratio (RR) for occurrence, standardized mean difference (SMD) for quality and ratio of means (ROM) for duration. Meta-analysis was not performed when fewer than four studies were available. A total of 4,663 articles were scanned. Eighteen studies were included in the systematic review and 16 entered at least one meta-analysis: documented occurrence (n = 8), patient-reported occurrence (n = 4), patient-reported-quality (n = 4), duration (n = 4). There was significant variability in settings, patients' clinical conditions, and professionals. No significant effect of interventions on documented occurrence (RR 1.54, 95% CI 0.84-2.84; I2 91%), patient-reported occurrence (RR 1.52, 95% CI 0.80-2.91; I2 95%), patient-reported quality (SMD 0.83, 95% CI -1.06 to 2.71; I2 99%), or duration (ROM 1.20, 95% CI 0.95-1.51; I2 65%) of end-of-life conversations was found. Data on frequency were conflicting. Interventions targeting multiple stakeholders promoted earlier and more comprehensive conversations. Heterogeneity was considerable, but findings suggest no significant effect of interventions on occurrence, patient-reported quality and duration of end-of-life conversations. Nevertheless, we found indications for interventions targeting multiple stakeholders to promote earlier and more comprehensive conversations.