HighlightsThree automatic boom height systems were compared: BoomTrac Pro (A), AutoBoom XRT (B), and UC5 Passive Roll (C).Boom leveling performance was quantified for three runs on each of three terrains for at least three speeds.System B kept the boom height significantly closer to target than Systems A and C.System B had significantly less boom height variability than Systems A and C.Abstract. Automatic boom height systems reduce the variability of agricultural sprayer boom height. Consistent boom height is important for three key reasons: to reduce uneven spray dispersion if the boom is too low, to reduce spray droplet drift if the boom is too high, and to reduce damage to the boom or crop if the boom is too low. No data is available comparing commercial boom height systems. Three leading North American automatic boom height systems were compared: John Deere BoomTrac Pro™ (System A), Raven AutoBoom® XRT (System B), and Norac UC5TM Passive Roll™ (System C) on a John Deere R4045 (Systems A and B) and RoGator 1100C (Systems B and C). Each system was evaluated with three test runs for at least three speeds over each of a mild, medium, and rough terrain course. Boom heights at the left and right outside sensors were measured with the AutoBoom XRT sensors. The accuracy of the automatic boom height systems was quantified with root mean squared deviation (RMSD), the Herbst-modified Hockley Index, and the fraction of points within 10 and 25 cm of target (f10 and f<25). With four exceptions out of 216 comparisons, System B significantly outperformed System A on the R4045 and System C on the RoGator for each metric, at each sensor location, at each speed, on each terrain. At 26 km/h on medium terrain, the RMSD for Systems A and C was 174% and 107% larger than System B, respectively. At 26 km/h on medium terrain, the fraction of points within 25 cm (f<25) was 56% and 21% higher for System B than Systems A and C, respectively. These results indicate System B kept the boom significantly closer to target with significantly less height variability. Keywords: Automatic control, Boom control, Spray boom, Spray dispersion, Spray drift, Spray height.