Absolute pitch (AP) refers to the rare ability to name the pitch of a tone without external reference. It is widely believed to be only for the selected few with rare genetic makeup and early musical training during the critical period, and therefore acquiring AP in adulthood is impossible. Previous studies have not offered a strong test of the effect of training because of issues like small sample size and insufficient training. In three experiments, adults learned to name pitches in a computerized, gamified and personalized training protocol for 12 to 40 hours, with the number of pitches gradually increased from three to twelve. Across the three experiments, the training covered different octaves, timbre, and training environment (inside or outside laboratory). AP learning showed classic characteristics of perceptual learning, including generalization of learning dependent on the training stimuli, and sustained improvement for at least one to three months. 14% of the participants (6 out of 43) were able to name twelve pitches at 90% or above accuracy, comparable to that of 'AP possessors' as defined in the literature. Overall, AP continues to be learnable in adulthood, which challenges the view that AP development requires both rare genetic predisposition and learning within the critical period. The finding calls for reconsideration of the role of learning in the occurrence of AP, and pushes the field to pinpoint and explain the differences, if any, between the aspects of AP more trainable in adulthood and the aspects of AP that are potentially exclusive for the few exceptional AP possessors observed in the real world. Keywords Absolute pitch. Pitch perception. Musical training. Perceptual learning. Perceptual expertise. Critical period Absolute pitch (AP) refers to the ability to name the pitch of a tone (e.g., naming a tone as "C") or to produce it without external reference tones (Takeuchi & Hulse, 1993; W. D. Ward, 1999). While the majority of us can effortlessly identify a countless number of faces, objects, and visual and auditory words, most people find it very difficult to name the twelve pitches, and professional musicians are no exception (Athos et al., 2007; Levitin & Rogers, 2005; Zatorre, 2003). The most extreme estimate states that, in every 10,000 people, there is one 'AP possessor' who can perform AP judgment accurately