Introduction: Diabetes mellitus is one of the most prevalent chronic noncommunicable diseases in the world. Objective: To validate by expert consensus the Nursing Outcomes Classification (NOC) self-management: diabetes (1619) and social support (1504), as well as to validate the intervention of social support for adults in the self-management of type 2 diabetes mellitus (DM2). Materials and Methods: A consensus study. Several phases were delimited for validation: the first was to validate the results and indicators; the second was to construct and validate the conceptual and operational definitions; and the magnitude of the selected indicators; and the third was to design and validate the intervention of social support for adults in the self-management of DM2. Results: 28 indicators were selected and validated by experts out of the 44 that make up the nursing outcome of self-management: diabetes, and 9 indicators out of the 12 that make up the social support outcome, both with a Content Validity Index (CVI) of 0.98. As for the intervention, a social support intervention was designed for the self-management of DM2, individualized, and made up of 4 sessions. The components of the intervention include generalities of DM2, healthy life habits, safe care, and emotional support. Discussion: Nursing professionals must evaluate people who experience diabetes, and their capacity for self-management and social support in order to provide appropriate interventions and evaluate their effectiveness. Conclusions: The study significantly evidenced the validation of the two nursing outcomes and their respective indicators, added to the conceptual and operational definitions, and their magnitude.