Graphical AbstractSummary:Tongue rolling is a common oral stereotypic behavior in dairy cattle characterized by a repeated circular movement of the tongue inside or outside of the mouth. We monitored tongue rolling in 8,158 lactating Jersey and Jersey-Holstein crosses on a large commercial dairy farm. The behavior was recorded over 3 consecutive milkings by cameras mounted in the center of two 80-stall rotary parlors. About one-third of the cows were observed tongue rolling during at least one milking, but this behavior was more common in Jerseys than in Jersey-Holstein crosses and more common in older than younger cows. We encourage more work on the stereotypic behaviors of cows on commercial farms to better understand the role of genetics and other developmental factors.