Regarding the three main features of scaffolding, namely, contingency, fading, and the transfer of responsibility, contingency entails the assistance adjusted to a learner's existing level of understanding. The present study investigated the effect of the model of contingent teaching on improving Iranian English as a foreign language (EFL) learners' overall writing performance (opinion essays), and in terms of writing components; namely, task response, coherence and cohesion, lexical resource, and grammatical range and accuracy. Moreover, the study aimed at investigating which component was mostly affected by the model. Based on convenience sampling, 60 female EFL learners of English in a language school between the ages of 20 and 30 were chosen from four intact classes. After conducting the Oxford placement test to ensure the homogeneity of the learners, the participants were then randomly assigned to one of two groups: experimental or control. The findings of the MANCOVA test revealed that the model of contingent teaching fostered EFL learners' opinion essay writing performance. Besides, the model of contingent teaching improved task response and the lexical resource more significantly. The study offers some practical implications for teacher trainers, teachers, and EFL learners which are discussed.