Actually, no. Most countries don't have a day of Thanksgiving, and of those that do, many are influenced by Thanksgiving Day held in the United States.
Those that are influenced by the American holiday are:
—Norfolk Island, Australia
Because American whaling ships would come to the island, the folks there picked up the Thanksgiving holiday and decided to continue it. Those that celebrate it do so on the last Wednesday of November, rather than the fourth Thursday like in the U.S.
While this is a day of Thanksgiving, it is not related to the American version, but it is a day of celebration to mark the anniversary of the U.S.-led liberation of the island after the military there assassinated their own socialist Prime Minister and set up a government.
This West African country began with freed black slaves from the United States in 1820. Their Thanksgiving is held on the first Thursday in November.
This is not the entire country, but rather a group of church goers at St. Peter's church In Leiden who mark the day, perhaps for their ancestors, who were part of the immigrants to Plymouth in the 1600s. A church service is held in the morning on Thanksgiving Day.
However, Protestant churches also observe a Thanksgiving worship service on the first Wednesday in November. It is not related to the American Thanksgiving and is not a public holiday.
THANKSGIVING DAY—THE REST
Thanksgiving there is held the second Monday in October, and was originally set up as a means to thank God for the harvest. Now, it's primarily observed in a secular manner. The day is observed everywhere in Canada except New Brunswick and Nova Scotia.
Thanksgiving is celebrated in October on the first Monday.
NO LONGER CELEBRATED
While the Philippines was under Spanish rule for quite some time, it became an American territory for 40 years after the Spanish-American War. Thus, the Philippines celebrated the American Thanksgiving during that period of time, suspended it during Japanese occupation during WWII, and then picked it up again through 1965.
Later, it was changed to September 21 as a way to mark the day martial law was imposed, but when President Marcos was thrown out of office in 1986, that celebration was discontinued.
REMAINING COUNTRIES WITH SIMILAR CELEBRATIONS
Germany, The United Kingdom, and India all hold Harvest Festivals as a means of giving thanks, while Japan actually has a Labor Thanksgiving Day. It is held on November 23 and started after the American occupation of Japan following the end of WWII. It is related more, however, to a Shinto harvest ceremony.
In addition, both Koreas observe Chuseok, a harvest festival held in early autumn lasting three days, and China and Vietnam hold a mid-Autumn festival which generally falls around the same day as the one in Korea.
There are numerous harvest festivals that aren't necessarily days of giving thanks, or at least not in the American tradition.
No, that would be silly.
Most countries did not commit a genocide on some native nation they colonized. :D
But I'm sure that every country have a type of holiday in the spirit of thanksgiving, when you get together with your family and have a feast.
The origin of such holiday are completely unrelated to the relatively new holiday that Thanksgiving in the USA and Canada.