Objective This review aimed to assess interventions designed to reduce harm from illicit tobacco (IT). We evaluated health outcomes, cost-effectiveness, the advantages and disadvantages of interventions, and contextual factors affecting implementation.

Data sources We searched MEDLINE and EMBASE databases from January 2002 to June 2024, the grey literature and undertook backward and forward citation searches of included studies without geographical restrictions.

Study selection Eligible study types included non-randomised trials, interrupted time series, before–after studies, economic simulations and mixed-methods studies. Case studies providing outcome data linked to specific interventions were also included. Studies were screened by multiple reviewers for eligibility.

Data extraction Data was extracted on geographical location and dates of interventions, descriptions of the interventions, contexts and outcome data relevant to review objectives which were checked by a second reviewer. Quality assessment was conducted using the Joanna Briggs Institute (JBI) critical appraisal tools appropriate for each study design.

Data synthesis Five studies and 16 case studies were included. These reported on a range of interventions (including track-and-trace systems, anti-counterfeit measures and communications campaigns) and outcomes (including tax revenue and population attitudes toward IT). There was some evidence for the effectiveness of track-and-trace systems. Case studies, predominantly on national-level interventions, reported decreases in IT market share and increases in tax revenue suggesting potential benefits of multicomponent strategies.

Conclusions There is promising limited evidence for interventions to tackle IT but they are seldom systematically evaluated. Comprehensive, independent evaluations are required to support policymaking and avoid tobacco industry influence in IT research.

PROSPERO registration number CRD42023452732.