Purpose Within the retail banking sector, the customer-centric business model has become an important and new business trend in recent years. The enhancement of the frontline service employees’ engagement and their customer-oriented behaviors are among the key factors affecting business performance (BP) in this sector of the banking industry. The purpose of this paper is to improve management decisions to enhance BP through examining the relationship between the frontline employees’ engagement and BP while taking into account the mediating effect of customer-oriented behaviors on this relationship. Design/methodology/approach A quantitative approach was adopted to conduct the present study, and the respondents were sampled from a large commercial bank in Iran using a structured questionnaire. Overall, 50 branch managers and 90 frontline employees were selected using random sampling. A confirmatory factor analysis was conducted to ascertain the validity and reliability of the observed items and a structural equation model was used for testing the proposed hypotheses and research framework. Findings The findings showed that customer-oriented behaviors mediated the relationship between the frontline employees’ engagement and bank’s branches’ BP. Higher levels of the frontline employees’ engagement enhance the customer-oriented behaviors. It was revealed that the frontline employees are engaged in their job and organization. Moreover, the engaged frontline employees listen carefully to customers, the customer’s problem is important to them and they complete their tasks precisely for customers. It has been confirmed that customer-oriented behaviors enhance branches’ BP. The bank frontline employees’ engagement and customer-oriented behaviors, in turn, affected the bank’s branches’ financial performance, process performance and employee performance compared with the bank’s key competitors. Research limitations/implications This study highlights the value of empirically establishing how employee customer-oriented behaviors are affected by employee engagement as an integrative construct bringing together BP. Practical implications This study can help improve BP by increasing the frontline employees’ engagement and their customer-oriented behaviors. This study suggests that organizations using the findings of this study could effectively assess their frontline employees’ engagement and their customer-oriented behaviors and then plan for improving them. Social implications This study offers a customer-oriented initiative as a social responsibility to be considered by retail banks. In light of the social exchange theory, the banks valuing customer-oriented can provide employees with knowledge, skills, values and support to develop motivation and abilities to demonstrate customer-oriented organizational citizenship behaviors. Originality/value Previous studies demonstrated that the employees’ engagement affects their customer-oriented behaviors. In addition, studies have referred to the effect of employees’ customer-oriented behaviors on BP. However, to the best of the knowledge, key questions regarding how the employees’ engagement at the branch level fosters customer-oriented behaviors and, in turn, the bank’s branches’ BP, remain unanswered. Hence, this study contributes to the investigation of the mediating role of the frontline employees’ customer-oriented behaviors in the relationship between their engagement and branches’ BP in the retail banking sector.