Background <p>Globally, the number of adults with hypertension doubled within the last three decades, and more than one billion adults have hypertension. Primary study results suggest family-based interventions (i.e., interventions in which at least one family member is involved) for individuals with hypertension have a positive effect on blood pressure (BP) and self-management behaviours (SMB). However, the evidence has not been systematically reviewed and synthesized. Thus, this systematic review and meta-analysis synthesizes the available evidence to explore the effects of family-based interventions on BP and SMB.</p> Methods <p>A comprehensive search of six databases: MEDLINE [Ovid], Cochrane Library, Scopus, EMBASE [Ovid], PsycINFO [Ovid], and CINAHL [EBSCO], and the grey literature ProQuest Dissertations and Theses Global was completed on March 14, 2025. The Cochrane Handbook for Systematic Reviews of Interventions was used to guide the review, and the PRISMA-2020 guideline was used to report the review. Search outputs were imported into EndNote and exported to Covidence for de-duplication and screening. Data extraction included study-level and intervention-level characteristics reported using the Template for Intervention Description and Replication (TIDieR). Risk of bias was assessed using Cochrane’s Risk of Bias (ROB) tool. Statistical meta-analyses were conducted using Review Manager 5.4.1 (RevMan) software.</p> Results <p>A total of 8,548 studies were identified in the search. After removing 3,826 duplicates, 4,722 studies remained for title and abstract screening. In total, 56 studies were included for a full-text review, and 19 studies were included for data extraction; 15 were randomized controlled trials (RCTs) and four were quasi-experimental studies. The duration of the interventions varied across studies and ranged from one month to 24 months. The overall pooled data indicated that family-based interventions reduced systolic blood pressure (MD = -7.74, 95% CI: [-10.24, -5.24], <i>p</i> &lt; 0.001; I² = 95%) and diastolic blood pressure (MD = -3.74, 95% CI: [-5.07, -2.42], <i>p</i> &lt; 0.001; I²= 91%) compared to usual care. Family-based interventions also contributed to improvements in adherence to SMB in individuals with hypertension.</p> Conclusion <p>Family-based interventions reduced both SBP and DBP, with better reduction for interventions delivered and evaluated within 6 months, and improved SMBs in individuals with hypertension. Furthermore, no studies from low-income countries were included in this review. Future research should examine the feasibility, accessibility, and effectiveness of family-based interventions in these settings. It is also recommended that future studies incorporate multiple components of an intervention, including practical sessions that are culturally tailored and theory-based, with ongoing reminders to improve the maintenance of hypertension behaviour change beyond six months.</p> Trial registration <p>The protocol of this systematic review and meta-analysis was registered with PROSPERO (registration number CRD420251010902).</p>