Libraries at the University of Dayton include:

• Roesch Library
• Marian Library
• School of Law Library
• School of Education and Health Sciences Curriculum Materials Center

Roesch Library, the main campus library, has more than 1 million print and electronic books, subscribes to more than 300 databases and provides access to more than 100,000 print and electronic journals. Through OhioLINK, a statewide consortium of college and university libraries, students, faculty and staff can access nearly 50 million additional items at member institutions, delivered on demand within a few days. A Federal Depository Library since 1969, the University provides access to government records in physical and electronic forms. Research assistance is available in person and via email, text, online chat and telephone. Students, staff and faculty can access group and individual study rooms, printers, computer workstations and technology-enhanced team tables; technology support from the University’s IT department and peer writing assistance through the Write Place is available during posted hours.

The Marian Library, based on the seventh floor of Roesch Library, houses the world's largest collection of published materials on the Virgin Mary. Its comprehensive collection is devoted to information about and references to the Virgin Mary found in works on Scripture, doctrine, history, tradition, art, culture, spirituality and devotion. Since its opening in 1943, the Marian Library’s outreach has taken many forms in order to reach all who wish to know, love and serve Mary. Publications include Marian Library Studies (original research on Marian topics); the twice-yearly Marian Library Newsletter; and Marian Studies (papers given at the annual meeting of the Mariological Society of America, which is headquartered at the Marian Library). The Marian Library’s collections can be accessed via the University Libraries’ online catalog. Hours and information on current art exhibits can be found on the website.

The School of Law Library in Joseph E. Keller Hall provides access to 300,000 printed materials, microfilms and legal databases on Anglo-American, foreign, comparative and international law. The Library also has a host of bar exam preparation materials and academic support resources. Its open-stack arrangement permits easy access to all materials, and Library faculty and staff are readily available to provide assistance to law school students, faculty and staff.

The School of Education and Health Sciences Curriculum Materials Center houses specialized education collections on the sixth floor of Brother Raymond L. Fitz Hall. Its collection includes professional education books and journals; literature for children and young adults; elementary, middle and secondary textbooks; standardized assessments; teaching aids; DVDs; CDs; electronic texts; charts; material kits; and other resources. A copier, four computer workstations, a comb binder, a laminator, Ellison and Accu-Cut die-cutting machines, and an assortment of letter and shape dies are available for student use.

The Libraries also oversee the University Archives and Special Collections. The University Archives document the University’s development into a top Catholic and Marianist institution of higher learning. Materials date from 1850, when St. Mary’s Institute was founded as a grammar school for boys, to the present. The archives include University records, alumni and faculty papers, student theses and dissertations, photographs and audiovisual recordings, and University publications. The U.S. Catholic Special Collection preserves records of the Catholic Church and Catholic life in the United States. Other Libraries special collections highlight sports, the arts, politics, rare books and the pursuits of UD alumni.