The Crystal Palace Rally was an historic gathering of Boy Scouts and unofficial "Girl Scouts" at the Crystal Palace in London on Saturday, 4 September 1909. The rally demonstrated the rapid popularization of Scouting with an estimated 11,000 boys attending with the prominent presence of Girl Scouts also being significant for the start of Girl Guides/Scouts. The rally was held a year and a half after the publication of Scouting for Boys and The Scout magazine, and two years after Robert Baden-Powell's demonstration Brownsea Island Scout Camp.
Some controversy occurred with attempts to exclude girls and Boy Scouts from the British Boy Scouts, Church Scout Patrols and other Scouts not registered with what would become the Boy Scouts Association, leading to challenges regarding the 4th Scout Law that "A Scout is ... a brother to every other Scout".
The Rally was a precursor to the later Scout Jamborees and World Scout Jamborees.
The concept of the Scouts' Own, a simple, non-denominational religious ceremony, was also introduced by H. Geoffrey Elwes at this rally.
Members of the local Scout Troop, 2nd Croydon (1st Crystal Palace Patrol), formed part of the flag party for Princess Christian, the member of the Royal family in attendance. As a result, the Group, which is still in existence, has the right to call themselves Princess Christian's Own. The Group still meet near Crystal Palace Park and regularly use Crystal Palace park for Scouting activities.
A number of girls also attended, dressed in Scout uniform and calling themselves "Girl Scouts". This was the first time Baden-Powell was able to discern how many girls were interested in Scouting, leading to the formal founding in 1910 of Girl Guides under his sister, Agnes Baden-Powell. Girls had wanted to become part of the movement almost as soon as it began. A contingent of girls from Pinkneys Green, Berkshire spoke to Baden-Powell at the Rally and asked him to let girls be Scouts. Baden-Powell decided to create a similar programme for them. In those days, for girls to camp and hike was not common, as this extract from the Scout newspaper shows: "If a girl is not allowed to run, or even hurry, to swim, ride a bike, or raise her arms above her head, how can she become a Scout?" In 1910, Baden-Powell and his sister Agnes Baden-Powell introduced the Girl Guides, in some other countries called Girl Scouts, a parallel movement for girls. Agnes Baden-Powell became the first president of the Girl Guides.