This study aims to evaluate the validity and practicality of a discovery-group learning model designed to enhance 21st century skills. The model includes a guidebook, teacher's book, student's book, and assessment sheet. The study involved three main stages: a preliminary study, prototype design, and evaluation. At the time of this article, the study had just reached the initial phases of prototype design. Before testing the model's effectiveness, the research materials underwent validation by reviewers (colleagues), experts (lecturers), and practitioners. Validation results indicated that the guidebook, teacher's book, student's book, and assessment sheet achieved an average validity score of 0.85, signifying very high validity. Practicality evaluations based on teacher feedback yielded scores of 91.7 for the teacher's book and 90.6 for the student's book. Similarly, student feedback for the student's book resulted in an average practicality score of 86.8. These findings demonstrate that the discovery-group-group learning model is highly effective for improving 21st-century skills among high school students, particularly in the context of Indonesian language learning. The research products, including the guidebook, teacher's book, student's book, and assessment sheet, exhibit both high validity and practicality, making them well-suited for classroom implementation.