Introduction. The article aims to investigate the forms of partners’ opportunistic behavior in a public-private partnership (PPP). The article highlights key features of a PPP that involves construction and operation of a railroad in Eastern Kazakhstan. Research methodology. This qualitative study employs in-depth interviews as a principal data collection method. Theoretical framework. The article’s theoretical underpinnings stem from highlighting the meaning of opportunism in general and from defining opportunistic behavior in a PPP in particular.