Background: After a stroke, up to 20% of patients suffer from aphasia. The preferred treatment for stroke-related aphasia (SRA) is regular speech and language training (SLT). In the present study, we investigated to what extent adjuvant repetitive transcranial magnetic stimulation (rTMS) might enhance recovery. While there is growing evidence of the positive effect of adjuvant rTMS on aphasia, no study has yet been based on an Iranian sample. Method: A total of 12 patients (mean age: 55 years; right-handed; 7 women) underwent treatment for SRA 1 month after stroke. The standard treatment consisted of regular 45-min SLT sessions 5 times a week for 2 consecutive weeks. Additionally, patients were randomly assigned either to adjuvant rTMS (5 times a week for 30 min) or to a sham condition (5 times a week for 30 min). At baseline and after 2 weeks of intervention, the degree of aphasia was assessed with the Farsi version of the Western Aphasia Battery. rTMS was applied to the inferior posterior frontal gyrus of the right hemisphere. Results: Speech and language improved over time, but more so in the rTMS than in the sham condition. Large effect sizes were observed for content, fluency, and the aphasia quotient; medium effect sizes were observed for command comprehension and repetition, while effect sizes were small for auditory comprehension and naming. Conclusions: Among patients with SRA, compared to a sham condition, adjuvant rTMS improved speech and language skills. The present results add to the accumulating evidence that rTMS as a neuromodulation technique has the capacity to enhance the effect of conventional SLT.