BACKGROUND: Breast and gynecological cancers contribute significantly to cancer-related mortality among Nigerian women. Despite the proven benefits of spousal support in improving cancer outcomes, male involvement in caregiving remains limited due to cultural norms, stigma, and systemic healthcare challenges. AIMS: This study evaluated the effectiveness of a couple-based virtual intervention in enhancing spousal support and improving the quality of life (QoL) of women undergoing cancer treatment in Nigeria. METHODS: An embedded mixed-methods design was employed involving 133 Nigerian couples, where women were receiving treatment for breast or gynecological cancer. The intervention consisted of an 8-week virtual peer support program for male partners, delivered via Zoom. Quantitative data were collected using validated instruments assessing spousal support and QoL, and analyzed using descriptive and inferential statistics. Qualitative data were obtained through semi-structured interviews with 21 male participants and analyzed thematically using NVivo 14. RESULTS: Post-intervention, significant improvements were recorded in spousal support across emotional (p = 0.0413), practical (p = 0.0296), financial (p = 0.0493), and health-related (p = 0.0313) domains. Women's QoL significantly improved in physical (p = 0.0109), psychological (p = 0.0452), social (p = 0.0024), and spiritual (p = 0.0417) domains. Thematic analysis revealed five key themes: emotional growth and support, understanding of partner's needs, building confidence, value of peer connections, and cultural or logistical barriers. CONCLUSIONS: The couple-based virtual intervention significantly improved male caregiving engagement and the quality of life of women undergoing cancer treatment. Findings support culturally tailored, gender-sensitive interventions in oncology care within resource-limited settings.