Ergonomic risk assessment tools are commonly used to evaluate the risk of musculoskeletal injuries during manual material handling (MMH) activities. This study aimed to compare and evaluate the performance of ten widely-used ergonomic risk assessment tools (REBA, RULA, QEC, NIOSH, WISHA, ManTRA, MAC, Washington state, ACGIH-TLV, and Snook’s tables) in assessing risk of injury to workers during various lifting, lowering, pulling, pushing, carrying, and prolonged static activities. Twenty-one different MMH activities including one- and two-handed, stoop/squat, symmetric/asymmetric tasks with various hand-load horizontal and vertical positions, weights, vibration, and task frequencies were assessed using the foregoing ten ergonomic risk assessment tools. A unique risk level classification was introduced to compare the outcomes of these tools. For a given MMH activity, the estimated levels of risk by different tools were found to be more consistent between the tools for high- and low-demanding tasks, and less consistent and in some cases contradictory for moderately-demanding tasks. RULA, ACGIH TLV, REBA, and QEC were the most and MAC and WISHA were the least conservative tools in their assessments. Comparison of these risk assessment tools revealed their similarities/dissimilarities and strengths/limitations thereby providing users with a comprehensive guideline for proper selection of these tools in practical applications.