The authors examined whether tailored self-management support (SMS) strategies reach patients in a safety net system and explored variation by language, literacy, and insurance. English-, Spanish-, and Cantonese-speaking diabetes patients were randomized to weekly automated telephone disease management (ATDM) or monthly group medical visits. The SMS programs employ distinct communication methods but share common objectives, including behavioral "action plans." Reach was measured using three complementary dimensions: (a) participation among clinics, clinicians, and patients; (b) patient representativeness; and (c) patient engagement with SMS. Participation rates were high across all levels and preferentially attracted Spanish-language speakers, uninsured, and Medicaid recipients. Although both programs engaged a significant proportion in action planning, ATDM yielded higher engagement, especially among those with limited English proficiency and limited literacy. These results provide important insights for health communication and translational research with respect to realizing the public health benefits of SMS and can inform system-level planning to reduce health disparities.