Many organisations have had to conduct strategy management process so as to attain competitive advantage in a very dynamic business environment. However, despite these strategies being well formulated and planned, they do not seem to deliver the desired outcomes. Several studies has been done over the years to determine the relationship between strategy implementation and performance of an organisation. The studies are not conclusive and that they do not look at how implementation of  specific organisational variable affects the performance. As such, the Islamic banks in Kenya have reported low profits with the main challenge has been in transforming strategies into action. The purpose of this study was to determine the effect of strategy implementation on performance of Gulf African Bank.. The specific objectives of the study were to assess how organisational structure of Gulf of African Bank has impacted on the bank’s performance, to assess effect of organisational culture in attaining organisational performance,to find out impact of organisational systems  in attaining organisational performance at GAB and to determine how employee reward influences the organisational performance of the GAB.The target polpulation comprised of the seven branches based at Nairobi region.The study employed stratified sampling technique and the data was gathered both through secondary and primary data collection techniques. Structured questionnaire was used to collect the primary data. The data was analysed using both descriptive and inferential statistics to illustrate the distribution of different variables across the sample population. The analysed data was then presented in form of tables and figures.The study found out that there are four main strategy implementation determinants which highly determine how Gulf African Bank performs. These include organisational structure, organisational culture, organisational systems and employee rewards. The study also found out that these strategy implementation determinants have varying extents of influence on the organisational performance at the bank. The regression analysis further revealed that strong relationship between these determinants and organisational performance at Gulf African Bank. The study therefore concludes that the nature of effect of the strategy implementationon the organisational performance is dependent on the individual determinants.The study further concludes that an evaluation and improvement of these strategy implementation determinants could result in improved organisational performance at Gulf African Bank.The study therefore recommends that the management in the bank to closely evaluate these factors and how exactly they affect both the strategy implementation process and the entire organisation performance.