Apnea of prematurity can be treated with a body-weight-adjusted dosage of caffeine. Semi-solid extrusion (SSE) 3D printing represents an interesting approach to finely tailor personalized doses of active ingredients. To improve compliance and ensure the right dose in infants, drug delivery systems such as oral solid forms (orodispersible film, dispersive form, and mucoadhesive form) can be considered. The aim of this work was to obtain a flexible-dose system of caffeine by SSE 3D printing by testing different excipients and printing parameters. Gelling agents (sodium alginate (SA) and hydroxypropylmethyl cellulose (HPMC)) were used to obtain a drug-loaded hydrogel matrix. Disintegrants (sodium croscarmellose (SC) and crospovidone (CP)) were tested for get rapid release of caffeine. The 3D models were patterned by computer-aided design with variable thickness, diameter, infill densities, and infill patterns. The oral forms produced from the formulation containing 35% caffeine, 8.2% SA, 4.8% HPMC, and 52% SC (w/w) were found to have good printability, achieving doses approaching to those used in neonatology (between 3 and 10 mg of caffeine for infants weighing approximately between 1 and 4 kg). However, disintegrants, especially SC, acted more as binder/filler, showing interesting properties to maintain the shape after extrusion and enhance printability without a significant effect on caffeine release.