This study aims to identify challenges in the moral development of adolescents at GMS Medan, such as the lack of active parental involvement in supporting their children's spiritual growth, the absence of routine and structured communication between youth ministry leaders and parents, and the fact that social dynamics outside the church often exert a stronger influence on behavior than the guidance received within the church. A qualitative, descriptive research approach was employed. The study subjects included the GMS Medan pastor, youth ministry leaders and mentors, Sunday School teachers, parents, and GMS Medan adolescents. Data were collected through interviews, observation, and documentation. The findings reveal that collaboration among the church community, Sunday School teachers, and parents regarding adolescent moral development at GMS Medan is implemented through regular coordination meetings involving pastors, ministry leaders, and mentors; parenting seminars; communication via WhatsApp groups; periodic ministry evaluations; and adolescent mentoring through "Connect Groups." Furthermore, the roles of the respective parties in this process are as follows: the pastor acts as a spiritual leader providing direction, teaching the Word of God, and overseeing the implementation of development programs; church leaders support the provision of facilities, policies, and funding, as well as the evaluation of ministry programs; Sunday School teachers lay the foundations of moral and character education from an early age; Connect Group leaders and youth mentors serve as mentors who accompany, guide, and model behavior for adolescents in their daily lives; and parents act as primary educators within the family, reinforcing the moral values taught by the church. Factors supporting and hindering this collaborative effort include the availability of development programs tailored to adolescent needs, close relationships between mentors and adolescents, parental support, and the commitment of ministry workers to their duties. Meanwhile, the inhibiting factors identified include the influence of social media and digital technology advancements, promiscuity, the academic and work-related busyness of teenagers, a lack of commitment among some youth toward ministry activities, a shortage of available mentors, and shifts in the mindset and culture of the younger generation. Nevertheless, GMS Medan continues to strive to overcome these obstacles through an approach that is adaptive, innovative, and grounded in Christian values.