National Criminal Justice Commission Act of 2015

Establishes the National Criminal Justice Commission.

Directs the Commission to: (1) undertake a comprehensive review of all areas of the criminal justice system, including federal, state, local, and tribal governments' criminal justice costs, practices, and policies; (2) submit to the President and Congress recommendations for changes in federal oversight, policies, practices, and laws designed to prevent, deter, and reduce crime and violence, reduce recidivism, improve cost-effectiveness, and ensure the interests of justice at every step of the criminal justice system; and (3) disseminate to the federal government and to state, local, and tribal governments a report that details its findings and supplemental guidance regarding the criminal justice system at all levels of government.

Expresses the sense of Congress that the Commission should work toward unanimously supported findings and supplemental guidance.