Type 1 diabetes mellitus is a complex disease, with self-control playing a key role in its effective treatment. Routine self-control requires high-order cognitive skills, e.g., planning, self-direction, compliance with medical recommendations, etc. All these pose a challenge for teenagers. The model of Responsible Self-Care developed by the World Health Organization takes into account not only health maintenance in diabetic patients, but also their cognitive ability to control their own attitude to treatment in order to achieve glycemic control. This study focused on the correlation between health self-control and neuropsychological profile in teenagers with diabetes. The sample included 38 diabetic patients represented by 13 boys and 25 girls aged 12–17. The study relied on the method of medical documentation analysis and the psychodiagnostic method, including the neuropsychological assessment battery by A. R. Luria and such questionnaires as Multidimensional-Functional Diagnostics of Responsibility, Self-Control Style, Locus of Disease Control, and Self-Efficiency in Disease. The correlation analysis confirmed a direct connection between the cognitive status and responsible behavior in teenagers with diabetes. Poor glycemic control and chronic hyperglycemia were associated with low test results in cognitive abilities, speech fluency, and memory capacity. Cognitive deficiency correlated with insufficient self-control, poor responsibility, and low self-efficiency, as well as with preference for external forms of control locus.