Thinking Day was first created in 1926 at the fourth Girl Guide/Girl Scout International Conference held at Girl Scouts of the USA's Camp Edith Macy (now called Edith Macy Conference Center). Conference attendees decided that there should be a special day for Girl Scouts and Girl Guides from around the world to "think" of each other and give thanks and appreciation to their "sister" Girl Scouts. The delegates chose February 22 as the date for Thinking Day because it was the mutual birthday of Lord Baden-Powell, founder of the Boy Scout movement, and his wife, Olave, who served as World Chief Guide.

In 1932, at the seventh World Conference, held in Poland, a Belgian delegate suggested that since birthdays usually involve presents, girls could show their appreciation and friendship on Thinking Day not only by extending warm wishes but by offering a voluntary contribution to the World Association. This is how the World Association's Thinking Day Fund began. The fund helps offer Girl Guiding/Girl Scouting to more girls and young women worldwide. Girl Scouts of the USA, through its Juliette Low World Friendship Fund contributes to the World Thinking Day Fund.

To emphasize the global aspect of Thinking Day, members at the 30th World Conference, held in Ireland in 1999, changed the name from Thinking Day to World Thinking Day.

See the World Thinking Day tour featuring photographs, craft ideas, songs and games from Girl Scouts/Girl Guides around the world. World Association members are invited to submit information, photos and activities to globalgirlscouting@girlscouts.org.