Business-IT alignment (BITA) has clearly become more important over the last decade. However, considerable difficulties remain when attempting to achieve a mature level of BITA. Therefore, research efforts which have resulted in a number of theoretical models have been able to help in devising and applying supportive tools for assessing different components of BITA. However, most of these efforts have either been produced in Anglo-Saxon countries or have been based on specific experiences in those countries. Consequently, they have tended to ignore a number of factors which differ in nature due to variations in cultural contexts. However, organisational culture has been given little consideration. Societal and organisational cultural aspects of BITA are particularly important because the majority of BITA models tend to focus more on the efficiency and effectiveness of BITA components rather than on trying to create ways in which how BITA can be achieved or maintained in different contexts. Therefore, the purpose of this thesis is to investigate the impact of societal and organisational culture on achieving BITA and influencing its maturity. The main result is an extended BITA model developed originally by Luftman, known as; Luftman’s Strategic Alignment Maturity Model (SAM), which is influenced by the organisational culture perspective. The research method and process advocated by Peffers et al. (2007) is used in the thesis to design the extended-SAM, consisting of six activities. The first of these activities involves identifying specific problems. This is achieved by an extensive literature survey of theories related to BITA, an explorative study of the impact of organisational culture on BITA and a classification of the general limitations of BITA. The second activity concerns the requirement for definitions of the designed artifact. The third activity is then specified in terms of designing the artifact; i.e. an extended-SAM. The design is based on constructed hypotheses of the potential impact of organisational culture elements (based on Smit et al.’s model (2008) on BITA attributes (based on SAM), and followed by an empirical study of 6 multinational organisations, for testing the hypotheses. Following that, in the fourth activity, various processes for extending SAM are demonstrated in different seminars within the IT management group at DSV, in conference papers and in different seminars of the Swedish research School of Management and Information Technology (MIT) (Forskarskolan Management och IT. In the fifth activity, the extended-SAM model is evaluated in 5 multinational organisations to test its practicality and utility. In the last activity, a journal paper (Paper III in the thesis) is presented to summarise all the processes. The communication is also carried out through pre-licentiate and the licentiate seminars. The extended-SAM shows in the result of the thesis that organisational culture is a clear factor that should be considered while assessing and studying BITA maturity. In addition, by considering organisational culture, assessing BITA is clearly shown as being more accurate and as reflecting a more detailed picture of the organisation’s BITA.