This study makes use of the Contrastive Interlanguage Analysis (Granger 1996) to examine the differences in use of modal auxiliaries may and might in the interlanguage produced by Norwegian and Japanese learners of English, and compares it to the use in language produced by native speakers. The material is extracted from the Norwegian and Japanese components of the International Corpus of Learner English, ICLE-NO and ICLE-JP respectively, and the Louvain Corpus of Native English Essays, and analysed according to a set framework for modal meaning based on Palmer (1990) and Collins (2002). To attempt to explain the differences between each learner group, references will be made to Contrastive Analysis and the Integrated Contrastive Model (Gilquin, 2000/2001). The main goal of this thesis is to compare and discuss how Norwegian and Japanese learners of English use may and might compared to native speakers, and if there are any indications of overuse or underuse. The assumption that there could be an overuse among Norwegian learners is mainly based on Aijmer s (2002) study on modal auxiliaries in Swedish. As for Japanese, modal auxiliaries are used in such a different manner that one would assume this would have some kind of effect on the interlanguage produced by Japanese learners. The main findings prove that while the use differs in terms of frequency, i.e. occurrences per 10,000, the distribution of each modal according to modal meaning is proportionally similar in all groups. However, the ways in which modals are used within each category also differs. Example sentences showing similarities and differences are provided to illustrate these differences. The thesis concludes that both Norwegian and Japanese learners of English seem to have a good understanding of how to use may and might, although there are a few prominent differences. Norwegian students overuse might to an almost extreme extent, while some Japanese learners seem to have problems with the syntactic features of modal auxiliaries.