Business rules shape the behaviour of a business and guide the behaviour of employees when conducting business. Therefore, business rules explain what is allowed and not allowed. It is argued that all organisations have business rules and engage in some form of relationship whether through competition or cooperation with other companies. In today’s business environment, organisations are embedded in relationships with other actors in order to gain access to resources that are needed. Therefore, each organisation’s business rules define their strategies and actions. The type of business rule behaviour which is applied by organisations encourages them to grow by taking market share from rivals or creating new markets. The aim of this study was to determine the influence of the rules of business behaviour on perceptions of the competitive banking environment in Uganda and its potential impact on certain outcomes. In this study, a quantitative research approach was adopted, as the study sought to investigate the relationships between variables. This study collected data through the use of a structured self-administered survey questionnaire which was distributed to 233 branches of banks in Uganda, totaling 700 bank employees. The survey yielded 529 usable questionnaires which were analyzed, using several statistical analysis techniques. A hypothetical model and measuring instrument of perceptions of the rules of business behaviour in the competitive banking environment within Uganda was developed. Six null-hypotheses were subjected to statistical analysis. The influence of three independent variables, namely, confrontational business behaviour, co-operational business behaviour and typologies of competition on the intermediate variable, perceptions of the competitive banking environment in Uganda were tested. The impact of these variables on three independent outcome variables, namely, organisational performance and customer loyalty and retention were also tested The empirical findings revealed that the rules of business behaviour have a significant relationship with perceptions of the competitive banking environment in Uganda. These results showed that confrontational behaviour as a rule of business behaviour can be classified as being direct or indirect. The study further revealed that banks should consider competitors as co-partners and not only as aggressors, indicating that co-operational business behaviour is statistically significantly related to perceptions of the competitive business environment in Uganda. The three typologies of competition, namely, defy attack, defense and debase attack are also positively related to perceptions of the competitive business environment in Uganda. The empirical results of the study also indicated that perceptions of the competitive banking environment have a positive relationship with outcomes such as organisational performance, customer retention and customer loyalty. This study contributed to the literature and body of knowledge regarding the impact of rules of business behaviour in the competitive banking environment in Uganda. This study could also assist banks, employees and customers alike to understand the different rules of business behaviour that exist and what strategies banks can employ to improve their position in the market. This study could also be replicated by other banks in other developing countries so as to ensure successful competition and the cooperation of banks as they engage in their activities in the banking industry.