Ademola, T. A.Mahmoud, A. M.Arawomo, P. O.2023-03-212023-03-2120191221-1265ui_art_ademola_on_2019Analele Universitatii din Oradea. Fascicola Matematica 26(2), 87-106http://ir.library.ui.edu.ng/handle/123456789/8109In this paper, a new class of third order nonlinear neutral delay differential equations is discussed. By reducing the third order nonlinear neutral delay differential equations to systems of first order, the second method of Lyapunov is engaged by constructing a complete Lyapunov functional and used to establish criteria that guarantee uniform asymptotic stability of the trivial solution and uniform ultimate boundedness of solutions. The obtained results are not only new but also include many outstanding results in the literature. Finally, the correctness and effectiveness of the obtained results are justified with examples.enNonlinear third orderDelay differential equationUniform stabilityUniform ultimate boundednessPeriodic solutionsArticle