Many have argued that concerns over health insurance reduce labor market mobility in the United States, causing a "job lock" effect. We take advantage of the novel natural experiment created by the Affordable Care Act's dependent coverage mandate to estimate the magnitude of the job lock effect for young adults. Using the 2008-2013 Current Population Survey and a difference-in-difference research design, we find that the expansion of dependent coverage did not increase job mobility, suggesting that job lock is not a major concern for young adults.