This research studies language contact as a possible cause of differences between languages in their degree of transparency. As transparency is assumed to facilitate intelligibility and learnability, especially for adult L2 learners, it is hypothesized that in particular contact settings with many such learners, languages tend to show increasing transparency. The study tests this hypothesis by investigating transparency in Norwegian, which has been exposed to extensive contact with Low German and Danish, and the relatively isolated Icelandic language. Based on a set of opacity features formulated in Functional Discourse Grammar, the degree of transparency of the two languages is compared. The results show that, as predicted, Norwegian is more transparent than Icelandic, which seems due to an increase in transparency in Norwegian and general opacity maintenance in Icelandic compared to their ancestor Old Norse. The study thus supports the hypothesized relation between language contact and transparency.