Purpose – The purpose of this paper is to investigate the impact of religiosity on consumer attitudes and purchase intentions toward Islamic banks. Design/methodology/approach – The study takes place in the Tunisian context. Even though Tunisia is a Muslim country, the culture is considerably different from those of the Middle East or Malaysia (countries where the majority of studies on Islamic banks have taken place). Consequently, an adapted religiosity scale was developed to fit the study’s context. Then, the scale was pre-tested on a sample of 188 respondents. In order to test the research hypotheses, a second data collection, based on a convenience sampling technique, was undertaken, yielding a sample of 217 respondents. Findings – The religiosity variable was found to be tridimensional. Results show that the more a person fears divine punishment, the more he/she will develop a favorable attitude towards Islamic banks. Also, the more a person believes in Islamic laws, the more favorable his/her attitude towards Islamic banks. However, the relationship between religious involvement (practice and interest) and attitude toward Islamic banks is found to be insignificant. Other alternative models were tested and the results indicate that neither fear, nor beliefs, nor religious involvement has a direct effect on purchase intention. Thus, religiosity has an indirect effect on purchase intentions of Islamic bank services through attitude towards these banks. Practical implications – It is suggested that a communication strategy focusing on the compatibility of Islamic banks with Islamic beliefs and eliminating any doubt that Islamic bank operations are suspicious (from a religious point of view) could attract a segment of consumers who wish to be in harmony with the prescriptions of their religion. Islamic banks can better position their offers compared to conventional banks and improve the perception of actual or potential clients. The study offers some implications to managers of conventional banks as well. Originality/value – Previous studies have reported the strong impact of religion on Muslims’ attitude towards Islamic banks. The main contribution of this study is to show which dimension of religiosity has the most important impact on attitude and purchase intention toward Islamic banks.