This paper is concerned with a state feedback controller design method for neutral systems with a time-varying delay, considering uncertainties in the plant parameters, as well as in controller gain. The uncertainties are in additive form, affecting both the system matrices of the plant and the controller gain. The uncertainties that are assumed admissible are time-varying and norm-bounded. The neutral system is also subject to external disturbances. A robust stabilizing H-infinity state-feedback controller is synthesized under several conditions that are presented in the form of matrix inequalities. A new generalized type of Jensen integral inequality has been introduced for utilization in the derivation of the aforementioned results, which could thus have been relaxed via that approach. A feasible solution set is obtained using the well-known cone complementarity technique by solving a non-linear minimization problem subject to linear matrix inequalities. A numerical example with case studies concludes the present work. The results of the minimum achievable attenuation rate indicate considerable improvement in comparison with those reported in the literature.