Porcellio dilatatus is a species of woodlouse in the genus Porcellio belonging to the family Porcellionidae. This species is widespread in Europe, and has also been introduced to North America from Western Europe. They are 15 millimetres (0.59 in) long, are brown coloured and striped. They can be found feeding on alder leaves, but mostly feeds on organic food substrates, such as lettuce (Lactuca sativa) in the wild. It also feeds on inorganic metal salts.