The study aimed to test the effectiveness applying of the best practices theory of human resource strategy on the performance of the transport sector organizations in Dhofar Governorate Sultanate of Oman, and to investigate the nature of the relationships included in the conceptual model of the study. It also aims to identify the role of the third organizational behaviour variable (the middle variable) between best practices of human resources management and improving the organizational performance. The researcher adopted the descriptive approach and quantitative analysis based on the method of field survey to examine the hypotheses and verify the correlation of these variables among them, depended on the questionnaire study tool. Based on the nature of relationships in the conceptual model of the study, the researcher used in the measurement and analysis of hypotheses structural modelling (SEM) using the program (AMOS) version (22) because this method of features comparable to traditional statistical methods in its accuracy, flexibility, and the measurement of several hypotheses at the same time The existence of several intermediate variables, and after testing the relationships between the underlying factors, the results showed that the effectiveness of applying the best practices of the human resource management strategy affects the levels of improvement of organizational performance through the positive role of the organizational behaviour of individuals in the organizations under study. The study recommended the promotion of the participation of all levels of staff in the administrative decision-making process. Attention to human and moral aspects, and the promotion of the culture of the organization in adopting modern concepts in human resource management to adapt the aspirations of its employees in line with contemporary developments.