Although processing instruction (PI) has been a very popular grammar teaching method over the last years, there are, however, very limited if any attempts to explore different proficiency learners’ achievements using this approach. This study was, therefore, an attempt to investigate the role of PI in possibly bringing about enhanced acquisition of three grammatical structures: regular past tense, causatives and relative clauses. In addition, it sought learner’s attitudes towards PI as it is believed that the success of an approach is highly dependent upon the viewpoints of its practitioners and the students being exposed to it. Three proficiency groups of elementary (n = 42), intermediate (n = 38) and advanced (n = 40) EFL learners were compared. The results of a set of independent samples t-tests revealed significant effects for the use of PI in all the groups except for a lack of improvement for elementary learners’ production of the regular past tense structure. The analysis of the attitude questionnaire and learners’ further ideas on the effectiveness of PI revealed their appreciation of the integration of this instructional practice in their target language courses. The results are discussed in relation to effective grammar and writing pedagogy.
