A new, simple, rapid, precise, accurate and reproducible RP-HPLC method for estimation of Acalabrutinib in bulk form and marketed formulation. Separation of Acalabrutinib was successfully achieved on a Develosil ODS HG-5 RP C18, 5 µm, 15 cm x 4.6 mm i.d. column in an isocratic mode of separation utilizing Methanol: Phosphate buffer (0.02 M, pH-3.6) in the ratio of 45:55% v/v at a flow rate of 1.0 mL/min and the detection was carried out at 255nm. The method was validated according to ICH guidelines for linearity, sensitivity, accuracy, precision, specificity and robustness. The response was found to be linear in the drug concentration range of 12-28 mcg/mL for Acalabrutinib. The correlation coefficient was found to be 0.9995 for Acalabrutinib. The LOD and LOQ for Acalabrutinib were found to be 5.004 µg/mL and 15.164 µg/mL respectively. The proposed method was found to be good percentage recovery for Acalabrutinib, which indicates that the proposed method is highly accurate. The specificity of the method shows good correlation between retention times of standard solution with the sample solution. Therefore, the proposed method specifically determines the analyte in the sample without interference from excipients of pharmaceutical dosage forms.