Microfiltration (commonly abbreviated as MF) is a type of physical filtration process where a contaminated fluid is passed through a special pore-sized membrane to separate microorganisms and suspended particles from process liquid.

It is commonly used in conjunction with various other separation processes such as ultrafiltration and reverse osmosis to provide a product stream which is free of undesired contaminants.

Microfiltration usually serves as a pre-treatment for other separation processes such as ultrafiltration, and a post-treatment for granular media filtration.

The suspended liquid is passed though at a relatively high velocity of around 1–3 m/s and at low to moderate pressures parallel or tangential to the semi-permeable membrane in a sheet or tubular form.

A pump is commonly fitted onto the processing equipment to allow the liquid to pass through the membrane filter.