Training and development have been applied in many aspects for organization performance. The purpose of this study is to investigate the relationships between training and development and organizational performance. In addition, the study also analyzes the influence of organizational culture as a mediator in the relationship between training and development and organizational performance. The data are analyzed using descriptive and inferential statistics. IBM Statistical Package for the social sciences software (IBM-SPSS) version 23 and Smart Partial Least Square (SmartPLS) version 4.3 were used to evaluate the hypotheses of the study. The survey of the study involved 219 employees in courier service organizations in Malaysia. The finding of the study shows that there was a positive relationship between training and development and organizational performance. Furthermore, the finding also reveals that organization culture mediate the relationship between training and development and organization performance. Hence organizations should consistently train and develop their employees through formal and informal training programs as well as encourage employees to embrace organizational culture and values as well as cultivate the core values of organizational culture amongst employees to strengthen and improve organizational performance.