We study the band-gap renormalization (BGR) in semiconductor quantum wires. Assuming an electron-hole system in quasi-equilibrium, we employ the random-phase approximation (RPA) and beyond (e.g., local-field corrections) to calculate the electron and the hole self-energies. The plasmon-pole approximation to the static dielectric function ε(q) agrees well with the RPA result. Our results for the BGR are compared with the recent experimental measurements and other theoretical calculations.