The main purpose of this thesis is to demonstrate how organizational culture drives effectiveness on performance of construction companies in Taiwan and Vietnam. In an effort to deal with the issue, two cases studies which are in-depth investigations of organizational cultures in several big construction companies in the both countries were made using a quantitative method with questionnaire surveys. A model of organizational culture, which consists of eight dimensions, was generated and taken as a base for development of hypotheses, designation of the questionnaire. Empirical data reveal that, Feedback is having a large impact on performance in construction companies in both Taiwan and Vietnam. Mission has much impact in case of Vietnam, whereas unexpectedly no impact in case of Taiwan. It is a surprise to see Involvement has no impact on performance in both Taiwan and Vietnam as expected, and Societal-orientation has not any impact in construction companies in Taiwan while a large impact in the ones in Vietnam. It is noticeable that Speed has a negative impact on performance in case of Vietnam. On discussions of the results, it is suggested that leaders and managers in construction companies in Taiwan should only focus on Feedback while the ones in Vietnam should focus not only on Feedback but also Mission and Societal-orientation. It should be kept in mind the more Speed might result in worse performance in construction companies in Vietnam.