Oscillation of solutions of differential equations enjoys wide range of applications, such as physical sciences, population growth and life sciences. In this paper, we discuss the oscillation of third-order nonlinear neutral delay differential equations with unbounded neutral coefficients and distributed deviating arguments. By using comparison principles, we relax the restricted conditions and establish new oscillation theorems, which extend and perfect some related results in the literature. Finally, our main results are illustrated by two examples.