Abstract Micro‐LED (light‐emitting diode) is an emerging technology that produces superiorly bright, efficient, and high‐resolution display. However, efficiency drop at small chip sizes is one of the major hurdles for cost‐effectiveness and ultra‐compact form factor. We demonstrate highly efficient submicron‐scale nanorod LEDs (nLEDs) passivated by the triple dielectric layers. The diameter, length, and wavelength at a peak external quantum efficiency (EQE) of nLEDs are 580 nm, 5 μm, and 460 nm, respectively. We report a peak EQE of 22.2 ± 0.3% with HfO 2 ‐based triple dielectric layer. We also explore the relation of indium fluctuation in multi‐quantum wells (MQWs) to sidewall effect of micro‐LEDs. We show that higher indium contents in MQWs successfully reduce non‐radiative recombination on sidewall of InGaN blue nLEDs.