Purpose: This paper highlights the current level of professional ethics standards in the construction industry in a developing economy and how ethics influences the quality of construction projects. Design/methodology/approach: A questionnaire survey and interviews were conducted on a selected sample from the construction industry in Malaysia, which has a fast-developing economy. Findings: The findings amongst others indicate that various forms of unethical conducts that could have a significant impact on the quality of construction were found in the construction industry. The findings also suggest that professional ethics is a pre-requisite to attaining a sustained and acceptable standard of quality in construction. Originality/value: apart from linking professional ethics to the quality of construction, this paper suggests ways to enhance professionalism among construction professionals to improve quality in construction including: imposing heavier penalties on those who are found to act unethically, attending ethics-training programmes and having regular ethics-awareness workshops. The construction industry needs to achieve internationally accepted quality levels to ensure that it is well positioned to support the nation's overall economic growth and to meet various challenges at the national and international levels.