OBJECTIVE: This systematic review investigates the characteristics, effectiveness and acceptability of interventions to encourage healthier eating in small, independent restaurants and takeaways. DESIGN: We searched five databases (CENTRAL, MEDLINE, Embase, CINAHL and Science Citation Index and Social Science Citation Index) in June 2022. Eligible studies had to measure changes in sales, availability, nutritional quality, portion sizes or dietary intake of interventions targeting customer behaviour or restaurant environments. We evaluated study quality using the Mixed Methods Appraisal Tool. Results are synthesised narratively, and interventions' impact on personal autonomy is assessed using the Nuffield intervention ladder. SETTING: Small, independent or local restaurants or hot food takeaway outlets, with no restrictions by year or country. PARTICIPANTS: Anyone selling or purchasing food in intervention settings (e.g. restaurant staff/owners, customers). RESULTS: We screened 4624 records and included 12 studies describing 13 interventions in 351 businesses. Most studies were of poor quality. Customer-level intervention components mostly operated on the lower rungs of the Nuffield ladder, and most had limited positive effects on increasing demand, measured as sales or orders of healthy options. Whilst rare, most interventions measuring business outcomes operated on higher ladder rungs and showed small positive results. There was insufficient evidence to investigate differences in impact by intervention intrusiveness. Acceptability was greater for interventions that were low-effort, inexpensive and perceived as not negatively impacting on customer satisfaction. CONCLUSIONS: Despite some evidence of small positive effects of healthy eating interventions on healthier purchases or restaurant/hot food takeaway practices, a weak evidence base hinders robust inference.