Abstract: Public universities heavily depend on government for funding, hence assessment and monitoring of the efficiency of these universities and Higher Education Institutions (HEIs) become necessary due their immense importance to nation building. As inputs and outputs are used in the assessment of the efficiency scores of the HEIs and universities, there have been other factors that affect the obtained efficiency scores but usually overlooked. These factors are not within the input and output variables and still have effects on the efficiency of the HEIs. Based on the factors, the empirical results show inconsistencies regarding the theories. Therefore, this study reviews the theoretical and empirical aspects of the efficiency of higher education institutions, universities and factors affecting the efficiency within the confine of public HEIs.