The present study investigated the pedagogical knowledge base underlying EFL teachers' provision of oral corrective feedback in grammar instruction. More specifically, we explored the consistent thought patterns guiding the decisions of three Iranian teachers regarding oral corrective feedback on grammatical errors. We also examined the potential variations across these patterns as a function of the participants' academic backgrounds. The data were collected through stimulated recall techniques. Content analysis of transcripts of stimulated recall sessions revealed 19 pedagogical thought categories which were classified into three major themes of professional knowledge, procedural knowledge, and personal knowledge. The results of statistical analysis revealed a significant positive correlation across patterns of thought categories. In addition, comparison of frequencies and average rates of reported pedagogical thought units indicated significant differences across the participants in terms of academic backgrounds. Implications of the findings for teacher professional development and suggestions for further research are provided.