Insulin pens have made a dramatic impact on diabetes care, with evidence suggesting that they promote performance of self-care and reduce negative health outcomes for people with diabetes. Human-centered design (HCD), practiced by IDEO for over 40 years and together with Eli Lilly for over 15 years, has helped to design insulin pens that evolved with the needs of people with diabetes. HCD employs unique methods that help to uncover people’s needs and design with them in mind. The future of diabetes care is bright with the ongoing application of HCD methodology in this space.