Thai Airways (TG) Baggage Allowances
How much luggage am I allowed to check?

The luggage allowance for Royal First Class is 40 kg. (88 lbs.); for Royal Executive Class passengers: 30 kg. (66 lbs.); and for Economy Class passengers: 20 kg. (44 lb.).
Royal Orchid Plus Gold Card members are entitled to check an additional 20 kg. (44 lbs.). Royal Orchid Plus Silver Card members can check an additional 10 kg. (22 lbs.) of luggage.
Infants (not occupying a seat) are allowed 10 kg. (22 lbs.) excluding one fully-collapsible child stroller, pushchair, or infant-carrying basket.

For travel To/from Canada and the U.S.A., the following regulations apply:
Passengers in all classes of service, from First to Economy, are allowed two pieces of luggage. The sum of the three dimensions (length + height + width) for each piece cannot exceed 158 cm. (62 inches) and the weight of each piece cannot exceed 32 kgs. (70 lbs).
A Child (2-12 years) occupying a seat is entitled to the same free luggage allowance as an adult passenger.
An Infant (not occupying a seat) is entitled to one piece of checked luggage, the sum of whose three dimensions does not exceed 115 cm. (45 inches), plus one fully-collapsible child stroller or pushchair or infant-carrying basket.

ROP Golds get an extra piece, for a total of 3 pieces of luggage.

How many pieces of carry-on luggage am I allowed?

Each passengers may hand-carry one piece luggage the sum of whose dimensions (length+ height + width) does not exceed 115 cm. ( 56 + 46 + 25 cm) (44.85 inches, i.e. 21.5 x 18 x 9.75 inches) and which does not weigh more than seven kg. (15.4 lbs). Pieces exceeding these dimensions must be checked in at the Check-in counter prior to departure. A woman is allowed to carry a purse as well.

Source: http://www.thaiairways.com/Travel_De...owed to check?

As always, luggage restrictions may be overlooked at the discrection of the TG check-in agent.