The invention provides transgenic or non-transgenic plants with improved levels of tolerance to AHAS-inhibiting herbicides. The invention also provides nucleic acids encoding mutants of the acetohydroxyacid synthase (AHAS) large subunit, expression vectors, plants comprising the polynucleotides encoding the AHASL subunits containing single, double or more mutations, plants comprising one, two or more AHASL subunit single mutant polypeptides, methods for making and using the same, and methods of controlling weeds.