Men who have sex with men (MSM), and gender minority individuals who have sex with men, living with HIV and substance use disorders (SUDs) are less likely to be virally suppressed, which can lead to HIV transmission and negative health outcomes. This hybrid type 1 study will assess the efficacy, mechanisms, as well as facilitators and barriers to implementing the MATTER intervention, a virtually delivered 5-session text-enhanced psychobehavioral intervention designed to facilitate viral suppression by addressing internalized stigma and shame as barriers to engagement in HIV care among MSM and gender minority individuals living with HIV and SUDs in two locations with different levels of HIV resources (i.e., the Boston, Massachusetts and Miami, Florida metro areas). MATTER aims to mitigate the negative behavioral consequences of internalized stigma and shame on viral suppression by a) developing behavioral self-care goal setting skills and related self-efficacy, b) increasing metacognitive awareness (i.e., non-judgmental awareness of emotions and cognitions), and c) teaching and reinforcing compassionate self-restructuring (i.e., self- compassion), in addition to providing access to phone-based resource navigation. Scalable interventions such as MATTER are essential to our efforts to end the HIV epidemic in high priority regions.