Due to the emergence of bacterial resistance in phytopathogenic microorganisms, it is necessary to search for new treatment alternatives for these pathogens. Natural extracts are a potential source of bioactive compounds that can act against such bacterial strains. The antibacterial activity of Larrea tridentata against bacteria with public health importance has been documented; however, few reports cover pathogens associated with the agricultural sector. The aim of the present study was to evaluate the antibacterial activity of Larrea tridentata hydroalcoholic extract (LTHE) and fractions against phytopathogenic bacteria. LTHE was obtained by the maceration technique and then subjected to bipartition using solvents of different polarities. Clavibacter michiganensis sbsp. michiganensis, Pseudomonas syringae, and Xanthomonas campestris strains were used, and their antibiotic sensitivity was determined. The minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) of LTHE and its fractions (aqueous: LTAq-F; organic: LTEtOAc-F) were determined. LTHE and its organic fraction showed bactericidal activity against the three bacteria, showing better activity against X. campestris, exhibiting an MIC of 0.39 mg/mL and an MBC of 0.78 mg/mL. The results show that LTHE and its organic fraction have bactericidal activity in vitro against Clavibacter michiganensis sbsp. michiganensis, Pseudomonas syringae, and Xanthomonas campestris.