It is a good idea to still use a car window shade, even with tinted windows, especially with young children and babies. The effectiveness of the tint depends on how dark it is and whether it is designed to protect against UV rays. However, the type of tint you have may affect the type of sun shade you choose. If it is a factory window tint, then it should not be damaged by any type of car sun shade. However, if it is an after-factory modification you may want to avoid suction cups as they may damage the tint.