National Guard and Reserves Reform Act for the 21st Century

National Guard and Reserves Reform Act for the 21st Century - Makes an individual eligible for retired pay for non-regular (reserve) military service if such individual: (1) satisfies one of specified combinations of minimum age (between 55 and 60) and years of service (between 20 and 30); (2) performed the last six years of qualifying service in currently authorized categories of military service, but not while a member of a regular component, the Fleet Reserve, or the Fleet Marine Corps Reserve; and (3) is not entitled to any other retirement pay from an armed force or as a member of the Fleet Reserves.

Authorizes a member of the Selected Reserve to enroll for self or for self and family under the TRICARE program (a Department of Defense managed health care program).

Amends the Internal Revenue Code to provide a reserve component employment credit equal to the sum of the employment credit with respect to all qualified employees of the taxpayer and the self-employment credit of a qualified self-employed taxpayer. Limits the credit to $25,000 for each qualified employee. Disallows the credit for failure to comply with reserve member employment or reemployment rights, or when a reserve member is called or ordered to active duty for training.