International Journal of Neutrosophic Science IJNS 2690-6805 2692-6148 10.54216/IJNS https://www.americaspg.com/journals/show/4029 2020 2020 Department of Mathematics, Faculty of Science, University of Jordan, Amman 11942, Jordan Isra Isra Faculty of Information Technology, Abu Dhabi University, Abu Dhabi 59911, United Arab Emirates Wael Mahmoud Mohammad Salameh Department of Mathematical Sciences, United Arab Emirates University, Al Ain 15551, United Arab Emirates Jianhua Gong Department of Mathematical Sciences, United Arab Emirates University, Al Ain 15551, United Arab Emirates Ajmal Khan Department of Mathematics, Abbottabad University of Science and Technology, Abbottabad 22500, Pakistan Shahid Khan In this paper, we introduce and investigate new generalized subclasses of neutrosophic n-fold symmetric bi-univalent functions defined in the open unit disk U . These subclasses are characterized via four neutrosophic multi-parameters κ, ρ, γ, and β, which provide a flexible framework to capture the truth, indeterminacy, and falsity components inherent in geometric and analytic behaviors. Within this neutrosophic setting, we derive upper bounds for the initial coefficients |dn+1| and |d2n+1|, and establish generalized Fekete–Szeg˝o inequalities for the considered classes. The results obtained extend and unify several existing results in classical and neutrosophic bi-univalent function theory. Examples and corollaries are presented to demonstrate the sharpness and applicability of the results. 2025 2025 204 218 10.54216/IJNS.260419 https://www.americaspg.com/articleinfo/21/show/4029