One of the most important fields in education is library. The library is a fast-growing system. The traditional methods of maintaining it are no longer dynamic and efficient. For expeditious retrieval and dissemination of information and better service for the clientele, an application of modern techniques has become absolutely indispensable. A properly computerized library will help its users with quick and prompt services. Therefore, this Paper produces an efficient Online Library Management System (OLMS) for university campus. The main purpose of this Paper is to design and implement the (OLMS). The OLMS consists of two modules: External Pages Module and Internal Pages Module. The first module is with limited operation such as (viewing, searching and registration request). The second module for the personal account can do the operations like (storing, searching, viewing, borrowing, downloading and etc.). The system controllers are two types. The first one is the (Co_Admin) which can manage library operation. The second one is the administrator which can create and manage university libraries and also can create (Co_Admin) for each faculty library. The system can generate different types of reports and can also calculate the (fines) on the users, also any request or response will be done by E-Mail and short message service (SMS). The OLMS was designed and implemented by using (MySQL, HTML, CSS, PHP, JavaScript, JQuery, Ajax and Bootstrap) techniques. The system was tested in two phases: the first phase identifies the views and preferences of users with the specification of the system outputs, depending on the requirements of the proposed system. The second phase measures the abilities of the system through System Usability Scale (SUS) technique with the contribution of 26 potential users of the system and the recorded rate 76% as overall satisfaction of OLMS implementation. A reasonable degree of compatibility and harmony between the university and the system requirements of application has been found in the University of Zakho.