With a global economy and worldwide corporations operating nowadays in the market across the world, the consequences of unethical pro-organisational behaviour (UPB) do not relate to organisations only – they affect the life and well-being of others. The key part of my work was to explore the main drivers behind such behaviour on the ground of the theory of planned behaviour (TPB) using a closed-ended questionnaire and following a quantitative research methodology. Key factors have been reviewed and grouped according to behaviour determinants, the survey gathered data describing willingness to participate in UPB and willingness to change attitude based on behavioural determinants, and statistical analysis described correlations between them. The analysed data confirmed the importance of the leader’s opinion, team workers’ opinion, compliance with your company’s policy, and consequences for the organisation for people prone to participate in UPB participating in the survey. All those factors translated into the following organisational aspects: quality of leadership, organisational culture, clear company policy, and consequences for participation in UPB, which were described as a ‘clear organisational stance’. Using that approach is potentially the most effective way to reduce UPB occurrences within an organisation.