The main purpose of this study was designed to develop and validate an instrument titled “Teacher Motivation Assessment Scale (TMAS) for quality assurance in universities in Anambra State. Thus, this is an instrumentation study. From literature, five constructs that constitute the major elements of human motivation were identified. The constructs include attitude, reward, commitment, punishment and interest. Initially, a 50-item Motivation Assessment Scale was developed by the researcher for the purpose of face validation and field trial. The initial draft of the instrument was subjected to face validation by 2 specialists in educational research, 5 specialists in educational administration and 2 specialists in measurement and evaluation. Their comments and suggestions were then incorporated in a second draft of the instrument still consisting of 50 items. This was subjected to field trial using fifty lecturers drawn from tertiary institutions in Enugu state. The data from the field trail were subjected to factor analysis to determine the items that were valid and therefore qualified to be included in the instrument for use in the actual study. Based on the factor analysis, 30 items were found to be well loaded. Thus, the draft that was administered to the research subjects consisted of 30 items. Data from the research subjects were analyzed using factor analysis, the Cronbach Alpha and t-test. Out of the 30 items, 8 were dropped. The remaining 22 items were grouped into 9 factors. Out of the 9 factors extracted, only five factors have items substantially loaded on them while four factors did not have up to the minimum loading of four items on them and were therefore ignored (Meredith 1969). The 22 acceptable items were grouped under five motivational constructs with their item loadings. The test of reliability using the 22 items that survival the validation test revealed that the instrument is reliable. The determination of internal consistency of the instrument based on the influence of school location and job experience showed that most of the items of the instrument were stable across school location and job experience. The researcher therefore recommends that the TMAS be used by the management of universities, Deans of faculties and Heads of departments including teachers for quality assurance in universities in Anambra State. It is also recommended that the instrument be used for all categories of tertiary institution for quality assurance irrespective of personality or environmental variables. DOI: 10.5901/jesr.2013.v3n6p95