Type 1 diabetes mellitus (T1DM) is one of the most frequent chronic endocrine diseases in the paediatric population. As a result, this disease has a strong impact on psychological well-being. In line with this, emotional factors play an important role in adaptation. The aim of the present study protocol is to design an emotional abilities programme to improve metabolic control assessed by haemoglobin A1c (HbA1c) samples. Specifically, this intervention will be focused on adaptive coping strategies to deal with unpleasant emotions associated with T1DM. The primary aim of this project is to assess whether the employment of this new psychological intervention improves the emotional abilities of adolescents with T1DM.Two focus groups will be carried out for the design and evaluation of the programme following the APEASE criteria (affordability, practicability, effectiveness, acceptability, side effects/safety and equity). Behavioural change will be based on the Behaviour Change Wheel. Sixty-two participants from 12 to 18 years of age will be recruited at a public hospital and randomised to either an intervention or a control group. The intervention group will receive an emotional abilities training programme. The control group will receive usual educational intervention. The primary outcomes are metabolic control and emotional abilities. The secondary outcomes include emotional distress control, positive and negative affect, healthy habits, and quality of life. Data will be collected at baseline, immediately postintervention, and at follow-up visits at 6 and 12 months. A feasibility analysis will be conducted.The study has been approved by the Ethics Committee of Universidad Loyola Andalucía. Results will be submitted for publication in peer-reviewed journals and disseminated across the scientific community.NCT03734367.