The research aims to improve creative thinking skill of junior high school students through guided inquiry learning. Learning materials were implemented to improve student’s creative thinking skill developed using 4-D model. The subject of limited try-out guided inquiry model as many as 12 students on eighth grader students of SMP Negeri 4 Lamongan. The subject of broad try-out as many as 50 students of eighth grader of SMP Negeri 4 Lamongan in school year 2016/2017 on human respiratory system. Try-out design used one group pre-test post-test design. Data callecting used validation, observation, test, and questionnaire method. Data analysis technique used quantitative descriptive and qualitative. The result showed that learning materials have been developed in effective category viewed from: (a) increasing of creative thinking skill with medium category in limited try-out and very good category in broad try-out, (b) student gave positive respond with very good category toward guided inquiry-based learning. It is concluded that guided inquiry-based learning can be used to drill creative thinking skill of SMP student.