A growing body of evidence that supports the efficacy of mindful parenting as a suitable intervention technique to foster parenting skills and reduce the risk of parental stress. However, most of the progress has been limited to parents with children with disabilities, and there is little evidence about the effect of mindful parenting intervention involving non-clinical populations. This study aimed to examine the effects of an 8-week Mindful Parenting Training (MPT) on parenting stress, Parent–Child interactions, and cognitive emotion regulation strategies among mothers of typically developing preschool children. Forty mothers with high-stress levels according to Parenting Stress Index (PSI) were randomly assigned to a Mindful Parenting Training (MPT) group (n = 20) and a sham control group (n = 20). Questionnaires were administered at pretest, posttest, and eight weeks follow-up. A significant improvement was seen in parental stress, Parent–Child interactions, as well as adaptive cognitive regulation strategies in the MPT group compared with the sham control condition with large effect sizes. Moreover, maladaptive cognitive emotion regulation strategies and conflicts associated with mother-child interactions decreased. All changes were maintained up to 2 months after the intervention. The results provide strong evidence that mindful parenting training is a valuable intervention for mothers referred to mental health care because of parenting stress, problems in Parent–Child interaction, and maladaptive cognitive-emotion regulation strategies.