Dilution may refer to:
- Reducing the concentration of a chemical
- Serial dilution, a common way of going about this reduction of concentration
- Homeopathic dilution
- Dilution (equation), an equation to calculate the rate a gas dilutes
- Trademark dilution, a type of unlawful trademark use outside of the relevant market
- Stock dilution, the result of new shares of stock being issued by a company, thereby diminishing the percent ownership represented by previously existing shares
- Dilution gene, a gene that lightens the coat color of certain living things
- Expectational Dilution, the second album by the metalcore band Overcast