Abstract: Line operators in 3d topological QFT's are expected to have the structure of a braided tensor category. In turn, braided tensor categories tend to arise mathematically as modules for quasi-triangular Hopf algebras, a.k.a. "quantum groups." Nevertheless, it has been a notoriously difficult problem to explicitly locate these quantum groups in 3d physics. I will propose a general approach to solving this problem in the case of QFT's that admit topological boundary conditions, inspired by recent work in 4d Chern-Simons (by K. Costello and collaborators) and 3d Chern-Simons (by N. Aamand). Simple applications include finding quantum groups in Dijkgraaf-Witten theory (a.k.a. finite-group gauge theory) and topologically twisted 3d N=4 gauge theories. (Joint work in progress with T. Creutzig and W. Niu.)