ABSTRAKPenelitian pengembangan ini bertujuan untuk menghasilkan produk bahan ajar berupa modul berbantuan model pembelajaran advance organizer yang valid, praktis dan efektif untuk meningkatkan penguasaan konsep peserta didik pada materi suhu dan kalor. Desain penelitian yang digunakan adalah model 4D yang terdiri dari define, design, develop dan disseminate. Produk yang dikembangkan berupa Rencana Pelaksanaan Pembelajaran (RPP), Modul Ajar Berbantuan model Advance Organizer, dan instrumen tes berupa soal penguasaan konsep. Teknik pengumpulan data menggunakan lembar validasi, soal dan angket respon peserta didik. Data validitas dianalisis dengan analisis validasi ahli untuk menentukan nilai validitas perangkat. Peningkatan penguasaan konsep fisika dianalisis dengan menentukan standar gain dari hasil sebelum dan sesudah pembelajaran. Validitas Rencana Pelaksanaan Pembelajaran (RPP) sebesar 84,72%, Modul Ajar Berbantuan model Advance Organizer sebesar 82,07 % dan soal penguasaan konsep sebesar 76,85%. Reliabilitas RPP, modul ajar dan soal tes penguasaan konsep di atas 75% yang menunjukkan keseluruhan aspek yang dinilai termasuk dalam kategori reliabel. Modul juga efektif untuk meningkatkan penguasaan konsep fisika. Diperoleh N-gain sebesar 0,43 dengan kategori sedang. Berdasarkan hasil tersebut dapat disimpulkan bahwa bahan ajar yang dikembangkan valid, praktis serta efektif digunakan untuk meningkatkan penguasaan konsep peserta didik. Kata kunci: bahan ajar; advance organizer; suhu dan kalor; penguasaan konsep ABSTRACTThis development research aims to produce teaching material products in the form of modules assisted by advanced organizer learning models that are valid, practical and effective to improve students' mastery of concepts on temperature and heat material. The research design used is the 4D model which consists of define, design, develop and disseminate. Products developed in the form of a Learning Implementation Plan (RPP), Assisted Teaching Module with the Advance Organizer model, and test instruments in the form of concept mastery questions. Data collection techniques used validation sheets, questions and student response questionnaires. The validity data were analyzed by using expert validation analysis to determine the validity value of the device. The increase in mastery of physics concepts was analyzed by determining the standard gain from the results before and after learning. The validity of the Learning Implementation Plan (RPP) was 84.72%, the Assisted Teaching Module with the Advance Organizer model was 82,07% and the conceptual mastery questions were 76,85%. The reliability of RPP, teaching modules and concept mastery test questions were above 75% which showed that all aspects assessed were included in the reliable category. Modules are also effective for improving mastery of physics concepts. Obtained N-gain of 0,43 in the medium category. Based on these results it can be concluded that the teaching materials developed are valid, practical and effective to be used to improve students' mastery of concepts Keywords: teaching material; advance organizer; temperature and heat; concept mastery.