LR or Lr may refer to:
In computer science, LR parsers are a type of bottom-up parser that analyses deterministic context-free languages in linear time.
LRRIQ3 (Leucine-rich repeats and IQ motif containing 3), which is also known as LRRC44, is a protein that in humans is encoded by the LRRIQ3 gene.
LRC (short for LyRiCs) is a computer file format that synchronizes song lyrics with an audio file, such as MP3, Vorbis or MIDI.
Low-density lipoprotein receptor-related protein 5 is a protein that in humans is encoded by the LRP5 gene.