Penelitian dilatarbelakangi oleh rendahnya kemampuan berpikir kreatif siswa. Penelitian ini bertujuan untuk meningkatkan kemampuan berpikir kreatif siswa kelas XI-F2 SMA Negeri 3 Surakarta pada materi sistem pertahanan tubuh melalui penerapan model discovery learning berbantuan concept map. Penelitian merupakan penelitian tindakan kelas (Classroom Action Research) selama 2 siklus. Subjek penelitian adalah siswa kelas XI-F2 yang berjumlah 36 siswa. Data penelitian diperoleh dari lembar observasi, tes essay, hasil wawancara, hasil keterlaksanaan sintaks, dan dokumentasi. Teknik pengumpulan data melalui observasi, tes essay, hasil wawancara, dan dokumentasi. Validasi data menggunakan metode triangulasi. Analisis data menggunakan teknik analisis deskriptif kualitatif. Capaian rata-rata kemampuan berpikir kreatif pada kegiatan pra-siklus pada indikator berpikir lancar (fluency thinking) meningkat dari 55,56% (rendah) menjadi 78,24% (sedang) pada kegiatan siklus I, kemudian meningkat kembali menjadi 90,62% (tinggi) pada siklus II. Indikator berpikir luwes (flexibility thinking) meningkat dari 46,72% (rendah) menjadi 79,24% (cukup), selanjutnya meningkat lagi menjadi 85,76% (tinggi) pada siklus II. Indikator berpikir orisinal (originality thinking) mengalami peningkatan dari 23,26% (rendah) pada kegiatan pra-siklus menjadi 69,79% (cukup) pada siklus I, kemudian meningkat lagi pada siklus II menjadi 95,83% (tinggi). Indikator memerinci atau mengelaborasi (elaboration thinking) meningkat dari skor 36,80% (rendah) menjadi 78,70% pada siklus I, kemudian meningkat menjadi 89.23% (tinggi) pada siklus II.  Berdasarkan hasil tindakan siklus II, kemampuan berpikir kreatif siswa pada masing-masing indikator memperoleh capaian skor rata-rata sebesar >80?n telah mencapai target dengan kriteria tinggi. Hasil penelitian menunjukkan bahwa implementasi model discovery learning berbantuan concept map pada materi sistem pertahanan tubuh dapat meningkatkan kemampuan berpikir kreatif.ABSTRACTBerlian Rifki Fadhillah. K4321016. Supervisor I: Dr. Baskoro Adi Prayitno, S.Pd., M.Pd. Supervisor II: Dr. Harlita, S.Si., M.Si. IMPLEMENTATION OF THE DISCOVERY LEARNING MODEL ASSISTED BY CONCEPT MAPS TO IMPROVE THE CREATIVE THINKING SKILLS OF STUDENTS IN THE SUBJECT OF THE IMMUNE SYSTEM. Thesis, Surakarta: Faculty of Teacher Training and Education, Sebelas Maret University, Surakarta. July 2025 The research was initiated due to students’ insufficient creative thinking skills. This study aims to enhance the creative thinking skills of Grade XI Science Class 2 students at SMA Negeri 3 Surakarta on the topic of the body's defense system through the implementation of the discovery learning model assisted by concept maps. The research is a Classroom Action Research (CAR) conducted over 2 cycles, with 2 meetings per cycle. The research subjects are the 36 students of Grade XI Science Class 2. Research data were obtained from observation sheets, written tests, interview results, syntax implementation results, and documentation. Data collection techniques included observation, written tests, interview results, and documentation. Data validation used the triangulation method. Data analysis was conducted using qualitative descriptive analysis techniques. The average achievement of creative thinking skills in the pre-cycle activity on the fluency thinking indicator increased from 55.56% (low) to 78.24% (moderate) in Cycle I, and further increased to 90.62% (high) in Cycle II. The flexibility thinking indicator increased from 46.72% (low) to 79.24% (moderate), then increased again to 85.76% (high) in cycle II. The originality thinking indicator increased from 23.26% (low) in the pre-cycle activity to 69.79% (moderate) in cycle I, then increased again in cycle II to 95.83% (high). The elaboration thinking indicator increased from a score of 36.80% (low) to 78.70% in cycle I, then increased to 89.23% (high) in cycle II. Based on the results of Cycle II, students' creative thinking skills on each indicator achieved an average score of >80% and met the high criteria target. The research findings indicate that the implementation of the discovery learning model assisted by concept maps on the topic of the body's defense system can enhance creative thinking skills.