This systematic review aimed to determine whether the use of specific behaviour change technique (BCT) groups are associated with greater effectiveness for psychosocial interventions delivered to family and close friends (FCFs) impacted by addiction. A systematic search of peer-reviewed and grey literature published until August 2021 identified 32 studies in 38 articles. An established BCT taxonomy (93 BCTs clustered into 16 groups) was adapted (inclusion of seven additional BCT groups) and applied to 57 interventions. The meta-analyses indicated that some, but not all, FCF outcomes were improved by the exclusion of BCTs within several groups (Reward and Threat, Scheduled Consequences, Confrontation of the Addicted Person to Engage in Treatment, and Goals and Planning) and inclusion of BCTs within the Restoring a Balanced Lifestyle group. Addicted person outcomes were improved by the inclusion of some BCTs within several groups (Repetition and Substitution, Reward and Threat, Scheduled Consequences, and Restoring a Balanced Lifestyle). Relationship functioning outcomes were improved by the inclusion of BCTs within the Confrontation of the Addicted Person to Engage in Treatment group. Future research involving the development and evaluation of numerous interventions or comprehensive multi-component interventions that can address the various needs of FCFs, without counteracting them, is required. •First meta-analysis of behaviour change techniques in family/friend interventions.•Excluding operant conditioning-based techniques improved family/friend outcomes.•Including operant conditioning-based techniques improved addicted person outcomes.•Including confrontation-based techniques improved relationship functioning outcomes.•Various techniques may be needed to address multiple family/friend needs.