Electronic Journal of Differential Equations, Vol. 2013 (2013), No. 08, pp. 1-10. Title: Existence and uniqueness of anti-periodic solutions for nonlinear third-order differential inclusions Authors: Touma Haddad (Univ. de Jijel, Algerie) Tahar Haddad (Univ. de Jijel, Algerie) Abstract: In this article, we study the existence of anti-periodic solutions for the third-order differential inclusion $$\displaylines{ u'''(t)\in \partial\varphi(u'(t))+F(t,u(t))\quad \hbox{a.e. on }[0,T]\cr u(0)=-u(T), \quad u'(0)=-u'(T),\quad u''(0)=-u''(T), }$$ where $\varphi$ is a proper convex, lower semicontinuous and even function, and F is an upper semicontinuous convex compact set-valued mapping. Also uniqueness of anti-periodic solution is studied. Submitted September 28, 2012. Published January 09, 2013. Math Subject Classifications: 34C25, 34G20, 49J52. Key Words: Anti-periodic solution; differential inclusions; subdifferential.