Informal learning is understood as a complex emotional, cognitive and experiential process of learning during which the personal change of learner takes place. The article presents the findings of the qualitative study on the personal change of foster parents carried out in Lithuania, which reveals the subjective experience of informal learning of the foster parents fostering a non-relative child. By means of a narrative interview, 19 foster parents (12 women and 7 men) were interviewed in the study. The data were analyzed on the basis of the constructivist grounded theory strategy. The findings revealed that the personal change of foster parents takes place through conscious, intentional and purposeful informal learning in order to self-actualize and to become good foster parents. They themselves construct their way of learning during which they acquire new knowledge, rethink and reconstruct the knowledge they already have – all that leads to personal improvement. The personal change of foster parents also takes place through accidental, spontaneous, experiential informal learning, which is not always conscious or purposeful. While reflecting on their experience, foster parents see themselves in a new light; rethink their values and attitudes, thus getting to know themselves better. The findings of the study are important in order to highlight the role and significance of informal learning in the context of life-long learning. The findings may be a valuable contribution to the development of formalized training programs for foster parents and successful non-relative foster care.