The present study aimed at investigating the relationship between willingness to communicate, intercultural communicative competence, autonomy, and vocabulary acquisition of intermediate EFL learners. To this end, 150 intermediate EFL learners studying at different language institutes in Hamedan took part in the study by completing the Willingness to Communicate in a Foreign Language Scale by Baghaei (2012), the Autonomy Questionnaire by Soodmand Afshar & Bastami (2012), the Intercultural Communicative Competence Scale by Byram & Phipps (1997) and a vocabulary test of TOEFL. Moreover, for data triangulation purposes, 20 EFL students were randomly selected and attended a semi-structured interview. The results of three separate Pearson correlations revealed that there was a) no significant relationship between intercultural communicative competence and vocabulary acquisition, b) a significant relationship between autonomy and vocabulary acquisition, and c) a significant relationship between willingness to communicate and vocabulary acquisition of EFL learners. Moreover, the results of multiple regression analysis indicated that autonomy was a stronger predictor of EFL students’ vocabulary acquisition. Additionally, the results of content analysis of interviews revealed that autonomous learners had such features as being good guessers, being creative in formulating new strategies and being tolerant, which helped them in acquiring new vocabularies.
