Background and Objective: Considering the importance of learning how to write a proposal for students, this study was performed to develop an online tutorial for “How to write a Proposal” for students and to evaluate its usability. Methods: This study is a developmental research and tool design. “Gamified Online Tutorial based on Self-Determination Theory (GOT-STD) Framework" became the basis for designing the online tutorial "How to Write a Proposal". After compiling and evaluating the content and questions, the online tutorial was designed by observing the structural, educational, and game elements introduced in the GOT-STD framework. In the last step, the usability of the tutorial was evaluated from the perspective of 10 master's students of Kashan University of Medical Sciences. Findings: The usability evaluation results and the students' feedback indicate that the tutorial structure and content are suitable for the students. Some of the structural and content problems of the tutorial were also corrected. Among the positive points of tutorial from the perspective of students are the presentation of content in the form of short films, the possibility of re-reading, the possibility of using without time and place restrictions, the use of examples, practical assignments, step-by-step, good navigation system, communication With the tutorial manager, the appropriate scoring system, and finally, he pointed out that tutorial is fun, competitive and motivating. Conclusion: The usability evaluation results and the students' feedback indicate that the designed tutorial can be used as a suitable educational aid tool for medical students.