Abstract This article conducts a comparative study between Optimality Theory in linguistics (Prince and Smolensky 1993) and the Dorsal-Ventral Model of Speech processing (Hickok and Poeppel 2004). The study makes use of the descriptive-analytical method. In Optimality Theory there are two major types of constraints: Faithfulness and Markedness. According to this theory, linguistic forms arise from interaction between Faithfulness and Markedness constraints. In contrast, the Dorsal-Ventral model of speech processing has two dorsal and ventral streams. The ventral stream is for speech comprehension, and the dorsal stream is for speech production. Here we first compared the ventral and then dorsal stream with the Optimality Theory. By comparing the ventral stream with Optimality Theory, the selection of optimal phonological representation has been described. By comparing the dorsal stream, the selection of optimal phonetic representation has been described. Following this stage, clinical evidences are mentioned to increase the strength of research analyses, and finally conclusions are presented. The results show that Optimality Theory is also neurologically compatible with the Dorsal-Ventral model of speech processing. Since in Optimality Theory, it is constraints that determine the optimal output, the neural explanation of constraints is currently not possible. Keywords: Optimality Theory, constraint, dorsal stream, ventral stream, speech. Everant Journal ISSN: 2456-2653 Volume 08 Issue 01 January 2024 Doi: : https://doi.org/10.18535/sshj.v8i01.891 https:https://sshjournal.com/ A Comparative Study of Optimality Theory and Dorsal-Ventral Model of Speech processing Sadegh Eftekhary Far 1 *, Sayed Farid Khalifehloo 2 , Hashem Farhang Doost 3 , Majid Torabi Moghddam 4 1 2 Speech Therapist, PhD candidate in Cognitive linguistics, Ferdowsi University of Mashhad, Iran. Assistant prof. English Language Department, University of Sistan and Baluchestan, Zahedan, Iran 3 Speech Therapist and Phd of Cognitive Neuroscience, Lecturer at Tehran University of Social Welfare and Rehabilitation Sciences, Tehran, Iran 4 Asistant prof, Faculty of foreign Languages, Department of linguistics, Velayat University, Iranshahr, Iran Copyright : © 2024 The Authors. Published by Publisher. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0/).