This article explores the links between multilingualism, the personality trait Tolerance of Ambiguity (TA), and attitudes toward linguistic variation among 379 mono-, bi-, and multilingual adults who completed an online questionnaire. A self-reported high level of proficiency in multiple languages, short- and long-term residence abroad, and high education levels are linked to TA and positive attitudes toward linguistic variation. In addition, higher levels of TA are linked to more positive attitudes toward variation in language. In the discussion, a multidirectional causal relationship between multilingualism, TA, and language attitudes is discussed, and implications for research into the sociolinguistic development of second language learners are sketched out.