The acquisition of new skills in adulthood can positively affect an individual's quality of life, including their earning potential. In some cases, such as the learning of literacy in developing countries, it can provide an avenue to escape from poverty. In developed countries, job retraining in adulthood contributes to the flexibility of labour markets. For all adults, learning opportunities increase participation in society and family life. However, the popular view is that adults are less able to learn for an intrinsic reason: their brains are less plastic than in childhood. This article reviews what is currently known from neuroscientific research about how brain plasticity changes with age, with a particular focus on the ability to acquire new skills in adulthood. Anchoring their review in the examples of the adult acquisition of literacy and new motor skills, the authors address five specific questions: (1) Are sensitive periods in brain development relevant to learning complex educational skills like literacy? (2) Can adults become proficient in a new skill? (3) Can everyone learn equally effectively in adulthood? (4) What is the role of the learning environment? (5) Does adult education cost too much? They identify areas where further research is needed and conclude with a summary of principles for enhancing adult learning now established on a neuroscience foundation.