Named entity recognition is a problem in the research area of natural language processing and is usually defined as the automatic extraction of the names of people, locations, and organizations in natural language texts. In this study, a Wikipedia-based named entity recognition system for Turkish is introduced. It is well-known that resources like Wikipedia, which are created by internet users, are considerably important for topics like named entity recognition. We have first automatically compiled a large list of person names from Turkish Wikipedia. Then, we have developed a Wikipedia-based named entity recognition system for Turkish which utilizes this large list with other lists of person, location and organization named obtained from Turkish Wikipedia and a former rule-based named entity recognizer for Turkish. We have evaluated our system on different types of datasets and obtained promising results. Our system is a significant contribution to information extraction on Turkish texts since there are limited number of related studies carried out so far.