The following was included in TCTA's 2018-19 Survival Guide, the ultimate reference tool for Texas educators, and is current as of September 2018 but is subject to change.

Each district must maintain an average ratio of no more than 20 students for one teacher. For kindergarten through grade 4, the district may not enroll more than 22 students in a class except during the last 12 weeks of the year.

Districts with high migrant populations may exceed the 22-to-1 ratio during a different 12-week period than the last 12 weeks of the year, but the period must be specified by the district.

Districts that obtain waivers from the limit must provide written notice to parents of each affected students, unless larger class sizes are part of a District of Innovation plan. Districts must specifically identify how student safety will be ensured if PE class-size ratios exceed 45-to-1. '

Note: This is a popular District of Innovation exemption.