Infiltration

Infiltration may refer to:

Science, medicine, and engineering

 * Infiltration (hydrology), downward movement of water into soil
 * Infiltration (HVAC), a heating, ventilation, and air conditioning term for air leakage into buildings
 * Infiltration (medical), the diffusion or accumulation of substances or cells not normal to it or in amounts in excess of the normal
 * Infiltration/Inflow, leakage of groundwater into sanitary sewers

Other uses

 * Entryism, the infiltration by a political organisation of another, usually larger, organisation
 * In espionage, using double agents to join an enemy organization
 * Infiltration tactics, tactics developed by the German army in early 1915 that broke the trench-warfare stalemate on the western front
 * Urban exploration, exploring parts of towns, etc. which are normally off-limits
 * Infiltration (zine), a popular urban exploration zine/website created by Jeff Chapman (Ninjalicious)
 * Seon-Woo Lee (born 1985), professional electronic sports players, specializing in fighting games, who plays under the alias Infiltration
 * Infiltration (2017 film), a Canadian film
 * Infiltration (2022 film), Russian war drama film