This study titled “Efficacy of Injectable Platelet Rich Fibrin (I-PRF) with Xenograft Compared to Xenograft Alone in the Treatment of Two or Three-Wall Intrabony Defects in Stage III Periodontitis – A Randomized Controlled Trial” is being conducted at the Government Dental College. The study aims to evaluate whether the addition of injectable platelet-rich fibrin (I-PRF) to xenograft provides superior clinical and radiographic outcomes compared to xenograft alone in patients diagnosed with Stage III periodontitis presenting with two- or three-wall intrabony defects. A total of 42  patients will be recruited and randomly allocated into two groups: Group A will receive xenograft combined with I-PRF, while Group B will receive xenograft alone. All participants will undergo initial phase I therapy followed by open flap debridement and placement of the respective graft material. The primary outcome measure is change in Clinical Attachment Level (CAL) at  4 months, assessed using a UNC-15 probe. Secondary outcomes include probing pocket depth, gingival recession, linear bone growth assessed radiographically using RVG, and patient satisfaction measured with VAS score. This two-arm, parallel, open-label randomized controlled trial will have follow-ups at 1 and 4 months. Data will be statistically analyzed using appropriate tests with significance set at p < 0.05. Ethical approval will be obtained from the Institutional Ethics Committee.