This paper offers a systematic review of quantitative and qualitative studies on the main twelve-step mutual-help (TSMH) groups (excluding Alcoholics Anonymous) and four meta-analyses exploring the correlation between (i) duration or involvement in TSMH groups and; (ii) severity of symptoms or quality of life. Systematic review was conducted following PRISMA guidelines. Searches of databases (MEDLINE, PsychInfo), a register (ClinicalTrials) and citations were conducted, from inception through November 01 2022. Fifty five articles were included (24 quantitative, 27 qualitative, 4 mixed-methods), corresponding to 47 distinctive studies. 68% of these studies were conducted in North America, 17% in Middle East, 11% in the European Union and 4% in Australia. The most studied TSMH group were Gamblers Anonymous (28% of the 47 studies), Narcotics Anonymous (26%), Double Trouble in Recovery (15%), Overeaters Anonymous (19%) and TSMH groups for compulsive sexual behaviors (11%). The four meta-analyses pooled data from 9 studies. Pooled mean age ranged from 36.5 to 40.5. 80-81% of participants were male. TSMH attendance and involvement were negatively correlated with severity of symptoms (high and medium levels of evidence) and positively correlated with quality of life (low levels of evidence). Twenty-one qualitative papers reported factors influencing recovery: Social (n = 15), emotional (n = 9), spiritual (n = 8), self-identification or psychological (n = 6) factors. Review provides characteristics of TSMH groups others than Alcoholics Anonymous, with implications for both research and healthcare practice. The perspective to implement TSMH groups targeting ontological addiction, at the root of all addiction, is discussed.Protocol registration: Prospero registration number: CRD42022342605.