Is the interest rate on a car loan negotiable?

Often, yes, especially at a dealership, where the rate offered may include room above the lender's base rate. Your strongest leverage is an outside pre-approval: ask the dealer to beat it. Your credit profile, down payment, term and the vehicle also affect the rate. Negotiate the vehicle price separately from financing so a lower price isn't offset by a higher rate, and review the APR on the final contract before signing.