The study developed and standardized an Inventory for measuring Students' Integration into University Academic Culture named Inventory for Students' Integration into University Academic Culture (ISIUAC). The increase in dropout rates, substance use, cultism and other deviant behaviours in Nigerian universities makes it necessary for one to ask the extent to which university students are integrated into the university academic culture. This necessitates the development of standardized instrument for the assessment of students' integration into university academic culture. The Study employed an instrumentation design in which a five point scale inventory were developed and standardized. An initial draft of 60 item instrument was developed and standardized. After corrections a 58 item instrument emerged and was administered to 500 University students. The data collected were subjected to factor analysis. The result from factor analysis showed that 27 items loaded well on three factors with minimum loading of 035. The 27 items were administered to 1,000 students to establish norms. The norm for the entire instrument was 105.19, the norms of male and female students were 100.96 and 109.21 respectively. Cronbach alpha statistics was used to establish the reliability of the instrument, its result shows an internal consistency of 0.926 for the 27 items. Hypotheses were tested using t-test statistics; the result shows that there is a significant difference between the norms of male and female students. The manual of the ISIUAC shows the administration and scoring procedure of the inventory and its psychometric properties. The instrument ISIUAC is recommended therefore for assessing students' integration into the university academic culture.