The Journal of the National Cancer Institute (JNCI) is a peer-reviewed medical journal covering research in oncology that was established in August 1940.

It is published monthly by Oxford University Press and is edited by Patricia A. Ganz.

A related publication is Journal of the National Cancer Institute Monographs (JNCI Monographs), established in 1959, which publishes manuscripts from cancer and cancer-related conferences, as well as groups of papers on specific subjects related to cancer.

In January 1986, Cancer Treatment Symposia was merged with JNCI Monographs.

It is published bimonthly by Oxford University Press and is edited by Ronald Chen.