Serenus of Antinoöpolis was a Greek mathematician active in the 4th century CE, during the later period of the Roman Empire. He came from the Egyptian city of Antinoöpolis. Beyond this location and his approximate time period, no details of his personal life are known.

He is known for two surviving technical treatises written in Greek: On the Section of a Cylinder and On the Section of a Cone. These works study the shapes created when a plane cuts through a cylinder or a cone. In On the Section of a Cylinder, Serenus demonstrates that such a cut, if not parallel to the base, always produces an ellipse and explores its properties. On the Section of a Cone analyzes the conditions for producing different curves—like triangles, circles, ellipses, and hyperbolas—from such sections.

According to modern scholars, Serenus's primary significance lies in his role as a later preserver and transmitter of the classical Greek geometric tradition, particularly following the work of Apollonius of Perga. While not introducing major new discoveries, his clear treatises show the continued advanced study of geometry into late antiquity. His works were later translated and published during the Renaissance, helping to revive interest in ancient mathematical knowledge.