Background <p>Evidence on diabetes fatalism is largely based on cross-sectional data. This study investigated the longitudinal relationship between diabetes fatalism, clinical outcomes, and health-related quality of life (HRQoL) in African Americans (AA) with type 2 diabetes (T2D) using results from a 12-month RCT.</p> Methods <p>AA adults (n = 200) with poorly controlled T2D (HbA1c ≥ 8%) were randomly assigned to receive 12 sessions of 30&#xa0;min/week of technology-intensified diabetes education and skills training or usual care. Glycosylated hemoglobin A1c (HbA1c), systolic and diastolic blood pressure, and the Physical (PCS) and Mental Component Summary (MCS) scores of HRQoL were measured at baseline, 3-,6-,9-, and 12-months. Diabetes fatalism was measured at all time points using validated scoring of the diabetes fatalism scale and its emotional distress subscale. Longitudinal mixed models with random effects were run for each of five outcomes, adjusting for treatment, time, treatment-by-time interaction, and baseline measures.</p> Results <p>Diabetes fatalism was negatively associated with MCS over time (β = -0.10, 95%CI [-0.17, -0.03]). Emotional distress subscale scores were positively associated with HbA1c (β = 0.02, 95%CI [0.004,0.04]) and negatively associated with PCS (β = -0.16, 95%CI [-0.27, -0.06]) and MCS (β = -0.23, 95%CI [-0.34, -0.11]).</p> Conclusions <p>Higher diabetes fatalism scores are associated with lower MCS over time, and higher emotional distress subscale scores are associated with higher HbA1c, lower PCS, and lower MCS over time. This study establishes that the association between diabetes fatalism and diabetes outcomes is persistent over time, and the emotional distress component is particularly detrimental to outcomes.</p>