1. Problem Statement: Behavioral-emotional problems in preschool children are highly prevalent and, if untreated, lead to long-term mental health consequences. Many of these problems stem from mother-child relationship quality and insecure attachment. The main gap is the lack of a localized educational package empowering mothers through play.

2. Research Method: This mixed-methods study (qualitative+quantitative) uses a quasi-experimental pretest-posttest control group design with a 2-month follow-up. In the qualitative phase, the "Attachment-Based Play" package is developed through component extraction, validation by 5 experts via Delphi panel, and designing eight 90-minute sessions. In the quantitative phase, 30 mothers of preschool children are purposively selected and assigned to two groups.

3. Objectives: The primary objective is to design and validate the educational package and determine its effectiveness in reducing children's behavioral-emotional problems. Secondary objectives include reducing externalizing and internalizing problems and evaluating the stability of effects.

4. Contributions: Producing an evidence-based localized educational package for counseling centers and kindergartens that empowers mothers, enhances maternal sensitivity and parenting self-efficacy, reduces children's difficulties, and promotes mental health in Iranian families.