This paper presents the results of a study aimed at exploring the possibilities Twitter offers for pronunciation instruction. It investigates the potential of a Twitter-based approach based on explicit instruction and input enhancement techniques to help English Foreing Language (EFL) learners improve their pronunciation of segmental and suprasegmental features that are commonly mispronounced due to lack of conscious attention to form (i.e. noticing) or explicit instruction, lack of exposure to the target language, difficult sound-spelling correspondences, or a combination of these. Additionally, the study investigates the relationship between the learners' level of engagement and their pronunciation improvement, as well as the learners' reactions towards the approach adopted and the way they use social networking sites (SNSs). The study follows a quantitative design, with pre- and post-tests aimed at measuring the learners' pronunciation before and after training, a delayed post-test aimed at measuring whether gains were maintained over time, and two questionnaires that gathered demographic data from participants, their patterns of SNS usage as well as their perceptions towards the approach adopted. The study was conducted with 121 participants divided into control and experimental groups. The approach consisted in sending learners a daily tweet with concise explicit explanations about the target aspects and a link to a video/audio file illustrating the pronunciation of the target word in an authentic context. The results show that the instruction fostered significant improvements in the learners' pronunciation of the target features and that improvements were maintained over time. As for the relationship between engagement and improvement, a positive correlation was found between these two variables, but it was very weak. Finally, the participants' responses to the questionnaires reveal that they considered the tips received as useful and that they perceive Twitter as potentially advantageous for educational purposes.