This experiment is intended to determine the consequences of two artificial intelligence writing assistance tools, namely ProWritingAid and Grammarly, on the writing proficiency of Iranian Intermediate EFL learners. Additionally, the study seeks to ascertain which of these tools, ProWritingAid or Grammarly, exerts a more substantial influence on the writing competency of EFL pupils. A quasi-experimental study design was utilized. Through the Oxford Placement Test, a sample of 96 male students was selected from two private language institutes located in Marand, Iran. Two experimental groups and a control group were formed using a non-random allocation method. Each experimental group utilized one of the artificial intelligence writing aid technologies. Subsequently, an eight-session treatment phase was conducted. Then, one-way ANOVA was adopted to evaluate the results of the writing post-test and it pointed out that both experimental groups accomplished exceedingly well compared to the control group. In addition, it was observed that the group that utilized Grammarly exhibited significantly better performance in comparison to the group that used ProWritingAid. The study's conclusions have major ramifications for educators, language learners, and artificial intelligence writing aid technology developers. Educators have the opportunity to employ artificial intelligence driven writing assistance tools for the purpose of delivering prompt and customized feedback to students. Manuscript profile