According to the Quantity of Work rule (cf. current General Information catalog), an undergraduate student must have approval to register at UT-Austin for:

• more than 17 semester hours in fall or spring
• more than 14 semester hours in a twelve-week summer session
• more than 8 semester hours in a six-week summer term

A new Irregular Status Petition must be submitted each semester you plan to enroll for more than the normal maximum number of hours. New UT students are ineligible to request above the maximum hours for their first semester at UT.  
Over hours requests are due by 5pm in order to be processed by Mark-Anthony that evening during business days, so please plan accordingly.