L-forms are bacterial spheroplasts or protoplasts originating from normal bacteria following partial (spheroplasts) or complete (protoplasts) removal of the cell wall. The formation of L-forms can be either spontaneous (occurring during certain phase of growth) or artificial (suppression of the rigid cell wall by stimuli such as enzymes, heat-shock, or special L-form induction medium, etc.) Bacterial genera from which L-forms have been derived include: Agrobacterium, Bacillus, Bacterodes, Bartonella, Bordetella, Brucella, Clostridium, Corynebacterium, Erysipelothrix, Escherichia, Flavobacterium, Haemophilus, Listeria, Neisseria, Proteus, Pseudomonas, Salmonella, Sarcina, Serratia, Shigella, Staphylococcus, Streptobacillus, Streptococcus, and Vibrio.

This definition is in context to Microbiology. See more contextual defintions for L form (L-phase, L-phase variant).