Diabetes is a growing epidemic and a major threat to most of the households in India. There is little evidence on awareness, treatment, and control (ATC) among adults in India is limited. We estimate the prevalence and ATC of diabetes among adults across various sociodemographic groups and states of India. We used 2,078,315 individuals aged 15 years and over from the recent fifth round of National Family Health Survey (NFHS-5), 2019-21, that was carried out across all states of India. Diabetes individuals were identified as those who had random blood glucose above 140 mg/dL or taking diabetes medication or doctor diagnosed diabetes. Individuals who were measured as diabetic and (i) reported diagnosis were labelled as aware, (ii) reported taking medication for controlling blood glucose levels as treated and (iii) had measured blood glucose levels < 140 mg/dL as controlled. The estimates of diabetes prevalence, and ATC were age-sex adjusted, and disaggregated by household wealth quintile, education, age, sex, urban-rural, caste, religion, marital status, household size and state. Concentration indices was used to quantify socioeconomic inequalities and multivariable logistic regression was used to estimate adjusted differences in these outcomes. We estimated diabetes prevalence at 16.1% (15.9–16.1%). Among those with diabetes, 27.5% (27.1–27.9%) were aware, 21.5% (21.1–21.7%) were treated and 7% (6.8–7.1%) were under control. Across states of India, adjusted rates of ATC varied from 14.4% (12.1–16.8%) to 54.4% (40.3–68.4%), from 9.3% (7.5–11.1%) to 41.2% (39.9–42.6%), and from 2.7% (1.6–3.7%) to 11.9% (9.7–14.0%), respectively. Age–sex adjusted rates were lower (p < 0.001) in poorer, less educated, and social backward groups, as well as for male and residents of rural areas. Among individuals with diabetes, the richest fifth were 12.4 percentage points (pp) (11.3–13.4; p < 0.001), 10.5 pp (9.7–11.4; p < 0.001), and 2.3 pp (1.6-3.0; p < 0.001) more likely to be aware, getting treated, and having control, respectively, than the poorest fifth. The concentration index of ATC was 0.089 (0.085–0.092), 0.083 (0.079–0.085) and 0.017 (0.015–0.018) respectively. Overall, the ATC of diabetes is low in India. The ATC was much lower among adults belonging to poorer class and were less educated. Targeted intervention and management can reduce the diabetes burden in India.