Oryzalin is a herbicide of the dinitroaniline class. It acts through the disruption (depolymerization) of microtubules, thus blocking anisotropic growth of plant cells. It can also be used to induce polyploidy in plants as an alternative to colchicine.

Oryzalin's mode of action is inhibition of microtubule assembly, so its HRAC classification is Group D (Australia), Group K1 (global) or Group 3 (numeric).

Roughly 250,000 pounds (110 t) was used in the US in 2019, down from about 750,000 pounds (340 t) in 2010, and 1,000,000 pounds (450 t) in 1995 (by USGS estimates).