In today’s pharmaceutical landscape, there’s an urgent need to develop new drug delivery systems that are appealing and effective in ensuring therapeutic adherence, particularly among paediatric patients. The advent of 3D printing in medicine is revolutionizing this space by enabling the creation of precise, customizable, and visually appealing dosage forms. In this study, we produced 250 mg metformin paediatric gummies based on the semi-solid extrusion (SSE) 3D printing technique. A pharmaceutical ink containing metformin was successfully formulated with optimal flow properties suitable for room-temperature printing. Using a quality by design approach, 3D printing and casting methodologies were compared. The 3D-printed gummies exhibited better firmness and sustained release at earlier times to avoid metformin release in the oral cavity and ensure palatability. The texture and physical appearance match those of gummies commercially available. In conclusion, SSE allowed for the successful manufacture of 3D-printed sugar-free gummies for the treatment of diabetes mellitus for paediatric patients and is an easily translatable approach to clinical practice.