Abstract: The Lanham Act bars trademark infringement and false advertising in nearly identical and often overlapping language. In some circumstances, courts have interpreted the two provisions in the same way, but in other areas there has been significant doctrinal divergence, often to the detriment of the law. This Article argues that each branch of the Lanham Act offers important lessons for the other. Courts should rationalize their treatment of implied claims, whether of sponsorship or of other facts; they should impose a materiality requirement, such that the only unlawful trademark and false advertising claims are those that actually matter to consumers; and in false advertising cases, they should recognize that competitors have sufficient interests to confer standing when the advertisers’false statements are doing harm, rather than imposing increasingly elaborate barriers to suit. The present practice of interpreting the same language in substantially different ways lacks justification and has the effect of promoting the interests of the most powerful companies, whether they are asserting claims of trademark infringement against smaller entities or defending themselves against false advertising claims by competitors.