The research aims at defining the traditional and modern concept of school library. The aims and function of school library which encourages students to read and prepares an educated and a ware generation capable of developing the community in all its aspects.The school libraries in Iraq generally and in Nineveh province especially passed through many stages but the most important one is the issue of the school libraries law no. 54 in 1974 which established the scientific bases of the school library.The research has come up with many results the most important one is that there are school libraries in Nineveh province that hold a good collection of rare and valuable books. These obtained during the previous years of its life. Some libraries have but few books, other libraries have no books at all, and there are many examples of that.The study recommends that selection of school libraries collections of books should be done according to definite standards, as well as establishing a central school library for the directorate general of Nineveh education which resembles University of Mosul central library.