Treatment choices for depression are preference-sensitive (no "single best option"). However, factors or attributes that can enhance or inhibit patient choice have not been fully explored. To synthesize the qualitative literature on facilitators and barriers to treatment choice, from the perspective of people with depression and healthcare practitioners. A systematic literature search identified eligible qualitative studies (Protocol registration no. CRD42019151352). Findings from 56 studies were meta-synthesized using a thematic analysis approach. Overarching facilitators to treatment choice that resonated with both patients and healthcare practitioners included: a trusting and respectful patient-practitioner relationship; information and guidance tailored to the individual and their preferred level of involvement in the decision-making process; eliciting and incorporating patient preferences and individual needs in order to find the best patient-treatment match. Prominent barriers to treatment choice that emerged were: limited time available to explore treatment options; inadequate mental health training, knowledge, skills, and experience; lack of psychological treatment services and waiting times; inflexibility of services. By focusing on the factors identified, practitioners can facilitate patient participation in decision-making, which has the potential to improve engagement with treatment and outcomes for adults with depression.