Tennessee Code Title 49. Education § 49-6-314

(a) A parent or guardian of a student enrolled in any of the grades kindergarten through two (K-2) may elect to retain the parent's or guardian's student in the student's current grade level if the student has a documented academic or behavioral delay and the parent or guardian believes that retention may benefit the student.  If a parent or guardian elects to retain the parent's or guardian's student in the student's current grade level pursuant to this subsection (a), then, subject to subsection (b) and subsection (c), the LEA or public charter school in which the student is enrolled shall retain the student in the student's current grade level at the parent's or guardian's request.

(b) A student cannot be retained in any grade level more than once.

(c) This section does not supersede an LEA's or public charter school's obligation to comply with the Individuals with Disabilities Education Act (20 U.S.C. § 1400 et seq.), Section 504 of the Rehabilitation Act (29 U.S.C. § 794), Title VI of the Civil Rights Act of 1964 (42 U.S.C. § 2000d), the Equal Educational Opportunities Act of 1974 (20 U.S.C. § 1701 et seq.), or any other federal or state law related to students with disabilities and English language learners.

(d) The state board of education shall promulgate rules, including emergency rules if necessary, to establish the requirements for the documentation required to establish an academic or behavioral delay for purposes of this section.  The rules must be promulgated in accordance with the Uniform Administrative Procedures Act, compiled in title 4, chapter 5.