World Thinking Day is a celebration of ten million girls worldwide that has taken place on every 22 February since 1926. It remains a day for all Guides and Girl Scouts to think of each other and celebrate their sisters all around the world. World Thinking Day remains one of the most important dates in the guiding calendar, and every year the theme of the event encourages members to think about the big issues affecting them and their global community. Previous World Thinking Days have tackled the subjects of poverty, gender inequality, environmental sustainability and access to education. Each year the World Thinking Day Fund supports girls and guiding across the world.

22nd February was chosen as the date for Thinking Day because it was the joint birthday of Lord Baden-Powell, founder of the Scout and Guide movement, and his wife Olave, who served as World Chief Guide.

One of the traditions of Thinking Day is that members of the Guiding movement wear their uniforms to school to show others that they are part of the movement.