Delivery of psychological and psychosocial treatments by non-specialists in low-and middle-income countries (LMIC) is a growing strategy to address the global mental health treatment gap. However, little is known about which competencies are essential for non-specialists to effectively deliver treatment. Psychotherapy research in high-income countries suggests that effective treatment requires competency in common factors. Therefore, our objective was to identify how common factors are described in evidence-supported non-specialist interventions in LMICs. To meet this objective, we identified and coded common factors by reviewing 16 evidence-supported manuals for psychological treatments delivered by non-specialists in LMICs. World Health Organization (WHO) manuals and other non-proprietary manuals, with positive randomized control outcomes, were included in the review. Fifteen common factors were identified and described in most manuals: ‘promoting hope and realistic expectancy of change’ and ‘confidentiality’ were described in 15 manuals (94%), followed by ‘giving praise’ and ‘psychoeducation’ (88% of manuals), and ‘rapport building’ (81% of manuals). Descriptions of common factors were similar across manuals, suggesting that training and competency evaluation approaches can be harmonized across interventions. Compiling these descriptions from the manuals can inform foundational training in common factors for diverse cadres of non-specialists around the world.