Wannabe is the seventh best-selling debut single of all time, with more than 1.3 million CD singles and download sales, as well as being the longest-reigning number one by a girl group.
To celebrate the anniversary, the group have also launched the #IAmASpiceGirl campaign.
Through the campaign, the band are inviting all fans to take a trip down memory lane and share their stories to be featured on the Spice Girls website and socials as part of the celebration. Fans can send in their videos and messages via socials using the #IAMASPICEGIRL or send to spicegirls@umusic.com.
The group said: "The Spice Girls belong to everyone and that's why we want to mark 25 years of Wannabe by celebrating our incredible fans."
After their iconic 1996 debut single Wannabe topped the charts in 37 countries, the Spice Girls' debut album Spice went on to sell more than 31 million copies worldwide, becoming the best-selling album of all time by a female group.
The girls have gone on to sell more than 90 million records around the globe, releasing three studio albums and 11 singles and winning a host of awards including a BRIT Award for Outstanding Contribution to British Music.
In 2019, the group reformed for the Spice World - Tour minus Victoria, 47, who made the decision not to rejoin Geri, 48; Mel B, 46; Emma, 45; and Mel C, 47; for the stadium shows.