We demonstrate green emission from InGaN/GaN multiple quantum wells (MQWs) grown on m-plane sidewalls of GaN wires. To tune the emission wavelength, InGaN radial wells were grown by metal–organic vapor phase epitaxy (MOVPE) at decreasing temperatures ranging from 710 down to 620 °C to increase the In incorporation. A comprehensive investigation combining structural and optical analyses demonstrates that the green emission from the nonpolar m-plane wire sidewalls is achieved for the wells grown at 650 °C (namely, for 2.7 nm thick wells sandwiched by 11 nm thick GaN barriers). The observed emission wavelength of 500–550 nm is consistent with an average In-content of MQWs measured in the range of 24 ± 4% by energy dispersive X-ray (EDX) and atom probe tomography (APT). Single wires were electrically contacted and the green electroluminescence from m-plane facets was established on single wire-LED devices. This demonstrates the possibility to produce green emitters with core–shell wire LEDs elaborated by industrial and scalable MOVPE technique.