The issue of unethical behaviour in construction public contracting is not a new phenomenon and many initiatives have been put in place to curb such behaviour. However, ethical behaviour has shown no improvement over the years. Previous studies in the construction industry have focused on the nature of the unethical behaviour that takes place rather than exploring the means and strategies to tackle the problem. This necessitates research to identify the influencing factors of unethical behaviour in bidding in order to improve the business ' standards/processes in construction contracting. This involves investigating the ethical standards of contractors in preparing bids and the relationship with organisational policies that constitute formal ethical measures. The research was conducted in the Malaysian context, undertaken from a qualitative research design perspective. Data were collected from three case studies through observation, interviews and documentary evidence. The analysis was carried out in three stages: (1) coding, (2) context, mechanisms and outcome and 3. cross-case analysis. Some pre-determined concepts were used but the analysis remained open to emergent findings. This provided an in-depth understanding of how ethical standards come about and how these influence the bid preparation. The findings suggest a relationship between organisational policies and bidding team members' job performance. However, this relationship is more complex in regards to the ethical conduct of the bidding teams. In this regards, middle managers were found to have significant influence on the behaviour of team members and it is inferred that top management seek to control approaches used in the bidding process. Therefore, formalised procedures, such as anti-corruption pledges and standard operating procedures, have no impact on the ethical conduct of the bidding team members, as they do not provide any insight into the actual tasks. Similarly, although the clients' rules have an influence on ethical behaviour in bidding, such rules, however, are project-specific and do not always fit with routine activities. The findings call for more in-depth studies to improve our understanding about the ethical standards of construction organisations in different contexts. This will help regulators and practitioners become acquainted with areas for improvement