38 C.F.R. § 21.4022

A veteran, reservist, or eligible individual, who is eligible for educational assistance allowance or subsistence allowance under more than one of the provisions of law listed in this section, whether based on his or her own service or the service of another person, cannot receive such benefits concurrently. The individual must choose under which program he or she will receive benefits for the particular period(s) during which education or training is to be pursued. The individual may choose to receive benefits under another program (other than 38 U.S.C. chapter 33) at any time, but not more than once in a calendar month. The individual may choose to receive benefits under 38 U.S.C. chapter 33 at any time, but not more than once during a certified term, quarter, or semester.

(a) 38 U.S.C. 30 (Montgomery GI Bill—Active Duty);

(b) 38 U.S.C. 31 (Veteran Readiness and Employment (VR&E) Program);

(c) 38 U.S.C. 32 (Post-Vietnam Era Veterans' Educational Assistance);

(d) 38 U.S.C. 33 (Post-9/11 GI Bill);

(e) 38 U.S.C. 35 (Survivors' and Dependents' Educational Assistance);

(f) 10 U.S.C. 1606 (Montgomery GI Bill—Selected Reserve);

(g) 10 U.S.C. 1607 (Reserve Educational Assistance Program);

(h) 10 U.S.C. 106a (Educational Assistance Test Program);

(i) Section 903 of the Department of Defense Authorization Act, 1981 (Pub. L. 96-342, 10 U.S.C. 2141 note);

(j) The Hostage Relief Act of 1980 (Pub. L. 96-449), 5 U.S.C. 5661 note);

(k) The Omnibus Diplomatic Security and Antiterrorism Act of 1986 (Pub. L. 99-399); and

(l) Effective August 1, 2011, 10 U.S.C. 510 (National Call to Service).