Prevalensi anemia di Indonesia masih cukup tinggi sehingga anemia masih menjadi masalah kesehatan utama di Indonesia selain masalah kurang energi protein, kurang vitamin A, dan gangguan akibat kurang iodium (GAKI). Faktor utama yang menyebabkan sulitnya penurunan prevalensi anemia ini antara lain karena rendahnya cakupan dan kepatuhan remaja dalam mengkonsumsi tablet besi. Kurangnya pengetahuan akan pentingnya mengkonsumsi zat besi berupa tablet penambah darah tersebut yang akan menyebabkan meningkatnya kejadian anemia pada remaja. Tujuan dari penelitian ini Untuk mengetahui hubungan tingkat pengetahuan siswi tentang pentingnya mengkonsumsi tablet Fe dengan kejadian anemia saat menstruasi di SMP N 1 PAKEM, Kec. Hargobinangun, Kab. Sleman. Penelitian ini merupakan penelitian observasional analitik dengan pendekatan cross sectional. Pengambilan sampel menggunakan total sampling dengan jumlah responden 32 siswi. Pengambilan data menggunakan kuesioner dan cek kadar hemoglobin. Analisis data dengan uji chi square. Hasil penelitian menunjukkan sebagian besar responden berusia 14 tahun sebanyak 22 siswi (68,75%) dengan sumber informasi terbanyak berasal dari media elektronik. Siswi yang memiliki pengetahuan baik sebanyak 23 siswi, pengetahuan cukup 8 siswi, dan pengetahuan kurang sebanyak 1 siswi. Angka kejadian anemia menunjukkan bahwa sebagian siswi tidak mengalami anemia saat menstruasi yaitu sebanyak 26 siswi dari total 32 siswi. Simpulan: Ada hubungan yang signifikan antara pengetahuan siswi tentang pentingnya mengkonsumsi tablet fe dengan kejadian anemia saat menstruasi di SMP Negeri 1 Pakem Sleman.Abstract. The prevalence of anemia in Indonesia remains considerably high, making it a major public health issue, alongside problems such as protein-energy malnutrition, vitamin A deficiency, and iodine deficiency disorders (IDD). One of the primary factors contributing to the persistent high prevalence of anemia is the low coverage and compliance among adolescents in consuming iron tablets. A lack of knowledge regarding the importance of consuming iron in the form of blood-boosting tablets contributes to the increased incidence of anemia among adolescents. This study aims to determine the relationship between students' knowledge about the importance of consuming iron tablets and the incidence of anemia during menstruation at SMP N 1 PAKEM, Hargobinangun District, Sleman Regency. This research is an observational analytic study with a cross-sectional approach. The sampling technique used was total sampling, with 32 female students as respondents. Data were collected through questionnaires and hemoglobin level checks. Data analysis was performed using the chi-square test. The results showed that most respondents were 14 years old, with 22 students (68.75%) primarily obtaining information from electronic media. A total of 23 students had good knowledge, 8 had adequate knowledge, and 1 had poor knowledge. The incidence of anemia revealed that most students did not experience anemia during menstruation, with 26 students out of 32 not being anemic. Conclusion: There is a significant relationship between students' knowledge about the importance of consuming iron tablets and the incidence of anemia during menstruation at SMP Negeri 1 Pakem, Sleman.