Diabetes self-management and support (DSME/S) delivered by mobile health (mHealth) technologies can circumvent access barriers experienced by Hispanic/Latino (hereafter, Latino) individuals with type 2 diabetes (T2D), however, little is known about how participant characteristics and diabetes distress (DD) levels shape engagement with, adherence to, and clinical benefit from these interventions. This 3-paper dissertation aimed to elucidate these questions by examining: (1) the moderating effect of baseline DD on glycosylated hemoglobin A1c (A1c) improvements; (2) associations of participant characteristics and baseline DD with engagement and adherence outcomes; (3) changes in DD over time and relationships between baseline DD and changes in DD with changes in A1c, in the context of two mHealth randomized trials. Study 1 used data from the Dulce Digital study (N=126), which tested a 24-week long mHealth DSME/S intervention (Dulce Digital) versus Usual Care among Latino adults with poorly managed T2D. A statistically significant three-way interaction effect indicated that participants with moderate/high DD at baseline achieved significantly larger six-month A1c decreases following the intervention than those with no/low DD. Study 2 used data from the Dulce Digital-Me randomized comparative effectiveness trial (N=310), which enrolled Latino adults with poorly managed T2D to static or adaptive (automated vs. telephonic) versions of Dulce Digital. Older age, longer diabetes duration, limited health literacy, and greater baseline DD were significantly associated with completion of fewer ecological momentary assessments, while preference for Spanish over English language was associated with higher completion rates of health coaching calls. Study 3 used data from the Dulce Digital-Me trial and found that DD significantly decreased over the intervention period. Higher baseline DD was linearly associated with higher A1c post-intervention. A lack of significant person-level variability in changes in DD over time precluded examination of the association with changes in A1c. Findings highlight the value of mHealth interventions for Latino adults with T2D and also clarify for whom these mHealth approaches may be most appropriate. Directions for future research include further elucidation of the role of DD in A1c change, and testing adaptions (e.g., added psychosocial support) to current mHealth approaches to further enhance clinical, psychosocial, and engagement outcomes.