The first Christmas stamp
They are referred to in the Stanley Gibbons catalogue as "Christmas Greeting" stamps. Shown above, they feature a rose and zodiac signs.
Canada issued a stamp in 1898 which had Christmas written on it, but it was not specifically a Christmas issue. It was actually issued to mark the inauguration of the Imperial Penny Postage rate.
The first US Christmas stamp was issued in 1962.
For more on Christmas stamps, click here.