Vibration analysis is the cornerstone of vibration-based condition monitoring that analyzes a vibration signal, detects faults or anomalies, and diagnoses the operating conditions of a belt drive system. This data article contains experiments that collect vibration signals of a belt drive system at different levels of speed and pretension of the belt under varying operating conditions. The collected dataset includes low, medium, and high operating speeds at three levels of the belt’s pretensioned values. This article covers three operating conditions: normal or healthy operation using a healthy belt, unbalanced operation by adding unbalanced weight to the system, and abnormal operation using a faulty belt. The collected data provides an understanding of the performance of the belt drive system during its operation to identify the root cause of an anomaly when detected.