This thesis reports on research to develop the first adaptive learning system for the Arabic language. The research also develops the first robust translation of the Felder-Soloman Index of Learning Styles (ILS) instrument into Arabic. Literal translation of the ILS applied to a pilot study resulted in lower internal validity in the instrument than found in the English language versions. The research discusses the development of a translation protocol undertaken to improve the validity and internal reliability of the Arabic version of the ILS. The new Arabic version of the Felder-Soloman Index of Learning Styles (ILS) instrument has been applied to two Arabic speaking groups in different Faculties at the King Abdul-Aziz University in Saudi Arabia: The Arts and Humanities Faculty and the Economics and Administration Faculty a total of 1204 students. Further analysis indicates that the Arabic version of the Felder-Soloman Index of Learning Styles (ILS) seems to be an appropriate psychometric instrument to identify learning styles in Arabic speaking communities. The second major part of the research was to use the Felder-Soloman Index of Learning Styles (ILS) instrument to develop an adaptive learning styles system and evaluate its effectiveness. The Teacher Assisting and Subject Adaptive Material System (TASAM) was tested out on different cohorts of students. Results showed that students taught using the learning style adaptive system performed significantly better in academic achievement than students taught the same material without adaptation to learning style. The feedback of student’s Survey overall students seemed to have enjoyed using the TASAM system and there seemed to have been a positive impact on learning performance. The thesis also provides guidance on translations of psychometric instrument and developing adaptive learning system.