Business-IT alignment (BITA) continues to attract the interest of researchers and practitioners. Literature review reveals that the focus of past studies was investigated BITA mostly at (1) strategic level, in (2) private and commercial organisations, and in (3) developed countries. Thus, making a generalisation from these findings is difficult. The current study is aimed at shading light on the barriers of BITA based on a case study in a public organisation like The Federal Inland Revenue Service of Nigeria. The data was collected through semi-structured email interviews from business and IT managers as well as IT officers and also from internal organisational documents too. The data collected has been analysed using thematic analysis and has revealed six BITA barriers at tactical and operational levels like previous IT failures, lack of feedback mechanism, organisational structure, lack of standard infrastructure, insufficient time to acquire knowledge, and poor communication between the mangers.