This paper presents a review on Knowledge Management (KM) performance measurement in the past two decades. Various tools and techniques that have been developed are discussed and presented chronologically to show how KM performance measurement has changed during this period. Each tool and technique is evaluated and classified based on the types of measures and approaches used. This paper also proposes six new categories: traditional, advanced, deterministic, stochastic, general result oriented, and specific result oriented, to complement the previous classification schemes. Future research directions for KM performance measurement are identified and presented in a holistic framework to act as a guideline for new researchers who wish to embark on this field.