Duquesne University of the Holy Spirit (/djuːˈkeɪn/) is a private Catholic university in Pittsburgh, Pennsylvania, United States. Founded by members of the Congregation of the Holy Spirit, Duquesne first opened its doors as the Pittsburgh Catholic College of the Holy Ghost in October 1878 with an enrollment of 40 students and a faculty of six. In 1911, the college became the first Catholic university-level institution in Pennsylvania. It is the only Spiritan institution of higher education in the world. It is named for an 18th-century governor of New France, Michel-Ange Duquesne de Menneville.

Duquesne has since expanded to over 10,000 graduate and undergraduate students within a self-contained 49-acre (19.8 ha) hilltop campus in Pittsburgh's Bluff neighborhood. The school maintains an associate campus in Rome and encompasses ten schools of study. The university hosts international students from more than 80 countries although most students — about 80% — are from Pennsylvania or the surrounding region. Duquesne is considered a research university with higher research activity institution by the Carnegie Foundation for the Advancement of Teaching. There are more than 79,000 living alumni of the university including two cardinals and the current bishop of Pittsburgh.