The long-standing underachievement in the Indonesian national nursing competency examination (NNCE) has been a common concern, and there is limited information on the preparation program for this licensure examination. Objective: To develop an NNCE preparation program model and evaluate its effectiveness in increasing competency among nursing graduates. Design: A quasi-experimental study using participatory action research (PAR). Setting: Faculty of nursing of a full-boarding private university in Indonesia. Participants: The participants were selected with the purposive sampling method. The 23 course coordinators and clinical instructors met the inclusion criteria of having worked for at least five years as classroom teachers and at least one year as course coordinators or clinical instructors. The 85 nursing graduates met the inclusion criteria of having finished the internship program and planned to take the NNCE. Methods: The model was developed using PAR and the evaluation done to measure the increase in the competency level and the level of perceived readiness and satisfaction of both the participant educators and nursing graduates. Results: The proposed model consists of core components and essential concepts. The core components are a holistic preparation process, active involvement and participation, knowledge and skill specialty, sharp examination-taking and skills, motivation to join the program and self-confidence to pass the NNCE, and time commitment for the preparation program. The essential concepts consist of awareness and trust, desire to change, sense of responsibility, mutual collaboration, equipped and empowered to act, definite direction and goals, mentoring. The model's evaluation indicated a significant increase in competency level, overall perceived readiness for the national nursing competency examination, and degree of satisfaction with the preparation program. Conclusions: The implementation of the preparation model effectively increased the nursing graduates' competency level, and both the participating educators and nursing graduates were satisfied with its effectiveness.