Despite the growing literature on LGBTQ + individuals' mental health, there has been no publication of a systematic review focused exclusively on effective psychological interventions for same-sex couples (SSC). The aim of this review is to investigate whether there are any empirical quantitative studies evaluating the outcome of couple psychological interventions specifically delivered to SSC. Multiple databases were screened by two independent reviewers for studies published between Jan 1996-Dec 2017. Hand-searching included journals, books and grey literature. The PRISMA guidelines were followed. Pre-defined eligibility criteria, methodological quality assessments and qualitative synthesis of the results were applied. After reviewing 1,451 citations, 9 eligible studies were identified with 583 SSC. They represent five unique psychoeducational or psychotherapeutic interventions, namely Relationship Education, Couples HIV Testing and Counseling, Gottman Method Couples Therapy, Behavior Couples Therapy, and "Connect with Pride." The overall risk of bias of included trials was moderate. Affirmative outcomes were related to high satisfaction with the interventions and improvements on multiple variables such as health-related behaviors, relationship enhancement, drug/alcohol abuse. The current review confirms that SSC are still underrepresented in couple outcome research. There is preliminary evidence of possible benefits regarding couple interventions for SSC.