Parents and teachers of children with special needs face unique social-emotional challenges in carrying out their caregiving roles. Stress associated with these roles impacts parents' and special educators' health and well-being, as well as the quality of their parenting and teaching. No rigorous studies have assessed whether mindfulness training (MT) might be an effective strategy to reduce stress and cultivate well-being and positive caregiving in these adults. This randomized controlled study assessed the efficacy of a 5-week MT program for parents and educators of children with special needs. Participants receiving MT showed significant reductions in stress and anxiety and increased mindfulness, self-compassion, and personal growth at program completion and at 2 months follow-up in contrast to waiting-list controls. Relational competence also showed significant positive changes, with medium-to-large effect sizes noted on measures of empathic concern and forgiveness. MT significantly influenced caregiving competence specific to teaching. Mindfulness changes at program completion mediated outcomes at follow-up, suggesting its importance in maintaining emotional balance and facilitating well-being in parents and teachers of children with developmental challenges.