You didn't have enough deducted from your paychecks. You might need to give your employer a new W4 form. Do you have more than 1 job or married? Compare your return with last year's and see what's different. Do you have children? The Child Tax Credit has gone back to the old rules and are not as generous as last year. Or you made more and didn't get as much Earned Income Credit as before. Could be several reasons.