**Carl Groos Jockusch, Jr.** (born July 13, 1941 in San Antonio, Texas) is an American mathematician. He graduated from Alamo Heights High School in 1959, attended Vanderbilt University in Nashville, Tennessee, and transferred to Swarthmore College, Pennsylvania in 1960, where he received his B.A. in 1965 with Highest Honors. He then enrolled at the Massachusetts Institute of Technology. He is a member of Phi Beta Kappa and Sigma Xi. In 2014, he became a Fellow of the American Mathematical Society. He is a professor emeritus at the University of Illinois at Urbana-Champaign.

In 1972 Jockusch and Robert I. Soare proved the Low Basis Theorem, an important result in mathematical logic with applications to recursion theory and reverse mathematics.