This study investigated teachers' motivations to undertake professional development, in particular where postgraduate study is involved. Specifically, the study involved the development, design and implementation of a psychometric instrument to measure Christian teachers' professional development motivations. Influential factors identified in the Continuing Professional Education literature, and the Motivation Psychology literature (specifically from Expectancy-Value and Goal theories), were operationalized in the psychometric survey. The resulting instrument, the EMAPS Scale (Educators' Motivations and Attitudes towards Postgraduate Study) included 18 factors. Results of the study indicate that the subscales (factors) of the EMAPS Scale are substantially reliable (most alpha reliabilities being in excess of 0.80). Also, Confirmatory Factor Analysis indicate support for the factorial validity of most of the items and factors in the EMAPS Scale (with goodness-of-fit indices meeting criterion values in most cases). However, one section of the EMAPS Scale did not demonstrate substantial validity. For this reason further research with additional samples is warranted. (Contains 2 tables.)