An LED lamp or LED light bulb is an electric light that produces light using light-emitting diodes (LEDs). LED lamps are significantly more energy-efficient than equivalent incandescent lamps and can be significantly more than most fluorescent lamps. The most efficient commercially available LED lamps have efficiencies of 200 lumen per watt (Lm/W). Commercial LED lamps have a lifespan many times longer than incandescent lamps.

LED lamps require an electronic LED circuit to operate from mains power lines, and losses from this circuit means that the efficiency of the lamp is lower than the efficiency of the LED chips it uses. The driver circuit may require special features to be compatible with lamp dimmers intended for use on incandescent lamps. Generally the current waveform contains some amount of distortion, depending on the luminaires’ technology.

The LED lamp market is projected to grow from US$75.8 billion in 2020 and increasing to US$160 billion in 2026.

LEDs come to full brightness immediately with no warm-up delay. Frequent switching on and off does not reduce life expectancy as with fluorescent lighting. Light output decreases gradually over the lifetime of the LED.

Some LED lamps are drop-in replacements for incandescent or fluorescent lamps. LED lamps may use multiple LED packages for improved light dispersal, heat dissipation, and overall cost. The text on retail LED lamp packaging may show the light output in lumen, the power consumption in watts, the color temperature in Kelvin or a color description such as "warm white", "cool white" or "daylight", the operating temperature range, and sometimes the equivalent wattage of an incandescent lamp delivering the same output in lumen.