This paper extends the implicit contracts framework to allow for on-the-job search. It is shown that involuntary unemployment can arise in such a framework without placing any a priori restrictions on either wages or severance payments. The model also implies that firms will practice a two-tier system of adjusting their labor force. In the first stage, workers who receive outside job offers leave the firm. The second stage consists of firms hiring additional workers during good states of nature, and laying off workers during bad states of nature. Furthermore, during "bad enough" states of nature, firms will offer a severance payment or bonus for those who want to voluntarily leave, and then lay off workers without offering a large enough severance payment to compensate them for being unemployed.