In the Egyptian environment, joint audit is implemented voluntary and mandatory before the European Commission issues its report in 2010. It is implemented voluntary for first time in 1981 for the Egyptian Stock companies, insurance companies, and factoring companies. While, banks have been obligated to implement joint audit since 2003. In addition to mortgage finance companies, fund-raising companies, investor protection fund, investment funds, and depository companies and central registration must designate at least two independent auditors. The purpose of this paper is to investigate the impact of joint audit on audit planning quality in the Egyptian environment. By examining whether joint audit can affect on the initial audit planning, the comprehensive audit strategy, and the overall audit plan and program, as proxies for audit planning quality. To test our hypotheses, we use a sample of 400 professional auditors from different-sized auditing firms and academics from different Egyptian universities. The results of our multiple regression analyses show that joint audit has a significant positive impact on the initial audit planning. Moreover, we find that joint audit has a significant positive impact on the comprehensive audit strategy. We also find joint audit has a significant positive impact on the overall audit plan and program. The results of the additional analyses show that the majority of the respondents' opinions (93%) support the application of voluntary joint audit for all companies and (89%) support if one of the two appointed auditors is a non-big 4 auditor.