L Cells (Cell Line) are a type of cell line commonly used for biological research in laboratories. They are used for a variety of different aspects of research and can be derived from mammalian cells from both in vitro and in vivo sources. L Cells were originally derived from the continuous embryonic kidney cell line derived from the Campbell-Hamilton strain of the peritoneal macrophage of the mouse.

L Cells were found to be useful for recombinant protein expression, gene mapping, cell signalling, mutation detection and gene manipulation.