Modern information and communication technology is revolutionizing how courts function, reducing backlogs by speeding up case resolutions and improving citizen access to trial proceedings and disposition. Ethiopia’s system of justice has suffered from long delays that undermined public confidence in the rule of law and imperiled rights granted under the Constitution. Family law, that governs the family related cases, is an area which can potentially benefit much from ICT. To address such problem, this study attempts to design and develop a knowledge-based Decision Support System that can provide advice to judge, lawyers and facilitate the judgment service within family law customers. To this end, knowledge is acquired using both structured and unstructured interviews from domain experts which are selected using purposive sampling technique from ANRS Supreme Court and Bahir Dar zuryia woreda court office. Relevant documents analysis method is also followed to capture explicit knowledge. Then, the acquired knowledge is modeled using decision tree that represent concepts and production rules are used to represent the domain knowledge and knowledge-based system is developed using SWI Prolog editor tool. Thus, the overall total performance of the prototype system is evaluated. The prototype system achieves 85% and it is a good performance and meets the objectives of the study. However, to make the system applicable in the domain area for court decision makings additional study is needed like updating the rules in the knowledge base of the system automatically and incorporating a well designed user interface. Keywords: Knowledge-Based System, Decision Support system, family law, court advisory.