Purpose <p>Most injuries in mountain biking (MTB), including traumatic brain injuries (TBIs), are caused by falls. Risk for TBI during a fall depends largely on whether impact occurs to the head. There is a lack of evidence on the frequency and risk factors for head impact during MTB falls. We addressed this knowledge gap by analyzing videos of real-life falls in recreational and competitive MTB.</p> Methods <p>Publicly available video footage was collected from the internet of falls in recreational MTB (n = 150) and falls in competitive MTB (n = 150). Each video was analyzed using a structured questionnaire. Logistic regression was used to test whether the probability for head impact depended on demographic, situational, and environmental factors.</p> Results <p>The head was impacted in 52.0% of falls. The probability for head impact did not differ between recreational and competitive MTB. The odds for head impact increased by falling forward (OR 4.9; 95%CI:1.7–14.1), falling due to wheel slippage (3.1;1.6–6.0) and falling while executing a jump (2.2;1.1–4.5). The odds for head impact decreased by dismounting from the bicycle during descent (0.11; 0.02–0.59), and with increased rider age (0.96; 0.93–0.99 per year).</p> Conclusion <p>Over half of falls in MTB resulted in impact to the head, and risk for head impact depended on characteristics of the rider, and characteristics of the fall. By identifying the types of falls in MTB that are most likely associated with head impact, our results can guide skills training and improvements in the design of protective equipment and MTB trails.</p>