Even learners with good language ability do not automatically engage in interactional encounters in the foreign language. Affective factors, such as speakers’ willingness to communicate (WTC), self-confidence and enjoyment of oral interaction play an important role in this (e.g. Dewaele & MacIntyre, 2014; MacIntyre, 2002). Little is known, however, about the effects of different instructional approaches on learner affect in oral interaction in the foreign language classroom. In a randomized experiment with Dutch pre-vocational learners (N = 147), we evaluated the effects of three newly developed instructional programmes for English as a foreign language (EFL). These programmes differed in instructional focus (form-focused vs interaction strategies-oriented) and type of task (pre-scripted language tasks vs information gap tasks). Multilevel repeated measures analyses revealed that learners’ enjoyment of EFL oral interaction was not affected by instruction, that WTC decreased over time, and that self-confidence was positively affected by combining information gap tasks with interactional strategies instruction. In addition, regression analyses revealed that development in learners’ WTC and enjoyment did not have predictive value for task achievement in EFL oral interaction, but that development in self-confidence did explain task achievement in trained interactional contexts. These results suggest that it is worthwhile for practitioners to address the development of self-confidence in their language lessons, and that they could do so my combining the use of information gap tasks with interactional strategy instruction that includes compensation-and meaning negotiation strategies.