Yes, depending on your ticketing arrangement.
Passengers travelling to Hong Kong International Airport with a Direct Air+Land booking are exempted. If your coach and flight are booked together under a single itinerary, the departure tax will be automatically waived. No further action is required.
If your coach ticket is purchased separately from the flight, you are still eligible for exemption. However, you will need to manually apply for a refund of the departure tax on the Airport Authority’s official page .