ABSTRACT Group performance in every organization is very important, as it depicts the overall performance of the organization. If various individuals in an organization cannot work as a group, then the organization’s performance-both financial and operational will never be maximized. Group efforts and team work is the major ingredient in every successful organization, hence, the need to make sure that the personality of every member in the group is okay for group/organizational goals to be achieved. Without good personalities in a group, there can never be a good group. The researcher used Ghana National Fire Service (Eastern Regional Office), as a case study to find out the effects of personality on group performance, as well as solutions to these negative effects. Concerning methodology, data used in compiling this research were gathered from both primary and secondary sources. The management and employees of Ghana National Service (Eastern Regional Office) were issued questionnaires. Text Books, Magazines and News Papers on personalities, groups and individual psychology were also used in compiling this research. Based on the findings revealed from the data analysis and interpretation, the researcher came up with some suggestions and recommendations. The major findings in this study include: the various personalities exhibited by employees in a group, and there are: the openness personality, conscientiousness personality, extraversion personality, and agreeableness personality. The negative effects of personality on group performance, which are: poor performance, delayed output, and incomplete output. The research also went ahead to find ways to improve group performance. These findings and recommendations, in view of the researcher, will help improve group performance in various business organizations in Ghana, if implemented by mangers of various business organizations..