T5 lamps need special ballasts to operate. In most cases, the T5 ballasts will not work with T12 or T8 lamps, although at least one manufacturer offers electronic ballasts that can operate either T5 or T8 lamps with appropriate wiring. T5 lamps operate at frequencies greater than 20 kilohertz. Instant start, rapid start, and programmed start electronic ballasts are available for T5 lamp operation.

Ballasts for T5 lamps are available for 120-, 277-, 240-, and 347-volt operations. Most T5 ballasts are more compact than T8 ballasts, although the dimensions vary depending on manufacturer and lamp type. For instance, the height, width, and length of a T5 ballast are 2.5, 3.00, and 36.20 centimeters (1.0, 1.18, and 14.25 inches) (Universal Lighting Technologies); or 3.18, 3.18, and 48 centimeters (1.25, 1.25, and 19 inches) (OSRAM SYLVANIA, Inc.). These small cross-section sizes allow luminaire designers to create thinner luminaires. Most manufacturers claim that their T5 ballasts have total harmonic distortion (THD) of less than 15%. This small amount of THD avoids potential imbalances in electrical lines that would damage wiring, transformers, or other equipment. Manufacturers claim these ballasts have highly efficient power factor values of more than 0.95. Most T5 ballasts carry class "A" sound ratings, so they are very quiet. The small diameter of the T5 lamp bulbs results in an increase in temperature, leading to cracks in the bulb. New ballasts for T5 lamps, therefore, are required to have "end of life" circuitry that ensures that power is shut off to the lamp when its functioning becomes impaired. The National Lighting Products Information Program's (NLPIP's) Specifier Reports: Electronic Ballasts gives more details of performance characteristics and physical features of T5 ballasts.