This paper addresses the World Bank funded study in which the University of Melbourne was commissioned to develop and validate a set of competency profiles and assessment strategies for primary school teachers in Vietnam. Through extensive expert consultation, 64 criteria which belong to 14 Requirements were developed within three broad strands: 'Personality and Ideology', 'Knowledge' and 'Pedagogical Skills'. In 2003, the draft profiles and accompanying assessment procedures were trailed (Griffin, Nguyen, Gillis and Mai (2006). In 2004, the validated profiles and assessment procedures were used to assess a further 25,000 teachers in 10 provinces in Vietnam. This paper reports on the findings from the final stage of validating the teacher profiles with 25,000 teachers. The paper will detail the process of checking if the 14 Requirements and their quality levels which were developed after the trial with 2180 teachers were valid and reliable instruments to measure the three strands of the teacher profiles. Analysis was also conducted to explore if there is any Requirement that exhibits differential item functioning due to assessment practice of different provinces. The findings are to identify further refinement in the profiles and ways to improve assessment practice for future roll-out.