I collect masks and, from my readings, they will be easy to find in Thailand. Am I correct? Thanks.

i have not seen as many there as in other places like bali....i'm sure in the markets and tourist areas like the nite market this sort of thing is available...others may have specific places for you to go....

elephant house off of suriwong road may be one place...

We were in Thailand twice; the first time I was on a mission to bring back a mask for my neighbor---found wonderful masks up near the Burmese border (near Chiang Rai) Found more good masks (albeit yesterday's antiques) in one of the markets in Hong Kong (if you're passing through there) on your way to or from. Oddly enough, didn't see much in the weekend market in BKK...but didn't look hard.
Have a wonderful time!

Many of the masks in Thailand come from Burma. As Bob notes, Bali and Java have lots of masks.

I think I recall seeing masks at the gift shop at Vinmanmek Palace.