Throughout the entire lifespan, individuals are required to adapt to the demands of changing developmental contexts and dynamic social environments. The potential modifiability of a person's cognitive and neural processes has been referred to as plasticity. One way to assess cognitive and neural plasticity is to apply training interventions and to measure the related changes in trained and untrained situations. Over the last decade, the literature on the effects of cognitive interventions has been growing rapidly, oftentimes focusing on the magnitude, scope, and maintenance of training-related benefits and their transferability to untrained tasks and abilities. Recent studies show that plasticity is present across the lifespan, although it seems to decline in older age, and that the long-term maintenance as well as the transferability of training gains strongly depends on the type and the intensity of the intervention. The findings from behavioral cognitive training research have also been accompanied by findings from cognitive neuroscience. The related observations oftentimes point to training-induced changes in a number of cortical and subcortical regions, which may be responsible for the magnitude of training and of transfer effects. Thus, cognitive training may be a promising tool for understanding basic mechanisms of adaptive behavior on the one hand and for designing applications and interventions within different disciplines in psychology on the other hand. However, not all studies have consistently shown beneficial effects of cognitive training and some questions that are critical for our understanding of plasticity are still unanswered. What are the key processes mediating training effects on laboratory tasks and in real world situations? Which characteristics of the training process and of the trainings situations mediate transfer effects? Are training effects subject to age-related changes? How are training-induced neural changes in the brain related to improvements in cognitive performance? How effective are training interventions in patients with specific cognitive impairments? To what extent can age-related cognitive decline be compensated by means of cognitive training? The focus of this Research Topic is on training-induced cognitive and neural plasticity across the lifespan. The goal is to provide a broad scope of state-of-the art research in order to enhance our knowledge regarding the mechanisms underlying plasticity. We invite contributions applying behavioral, computational, and neuroscientific approaches, reviews, and theoretical contributions. Contributions are also welcomed if they focus on the implications of cognitive training in applied fields like educational and clinical settings as well as rehabilitation and training science.