The concept for Gardaland dates to the early 1970s when Livio Furini, an entrepreneur from Verona, was inspired by a visit to Disneyland in California. Built on the eastern shore of Lake Garda at Castelnuovo del Garda, Gardaland opened on 19 July 1975, between Peschiera and Lazise. In 2004, Gardaland Hotel opened, which was the first hotel in Italy to provide themed accommodation. Merlin Entertainments took ownership of the park in 2006. A Sea Life aquarium opened on site in 2008. In the following years, more hotels were built. Gardaland Adventure Hotel opened in 2016 followed by the Gardaland Magic Hotel in 2019. Additionally, the first Legoland Waterpark in Europe was launched in the park in 2021.

Gardaland was forced to close during the COVID-19 pandemic but reopened on 13 June 2020, making it the first Italian amusement park to reopen after the COVID-19 lockdown. The maximum number of daily visitors in that season was restricted to 10,000 per day.

As a result of a global deal with Sony Pictures Entertainment, a variety of rides, food outlets and hotel rooms were developed across Merlin theme parks themed around the Jumanji film franchise. The park opened a ride called Jumanji - The Adventure for the 2022 season, featuring a large animatronic figure. The ride was the first theme park attraction to be based on the Jumanji franchise. In 2023, another Jumanji-themed attraction named Jumanji - The Labyrinth opened in the park, which is a walkthrough attraction featuring a mirror maze and jungle maze.

In 2025, the park celebrates its 50th anniversary with a remodelled area named Dragon Empire, set to launch in April. In November 2024, Gardaland announced an upcoming water dark ride for 2025 based on a new intellectual property registered by Merlin Entertainments named Animal Treasure Island. The 6,000 square metre ride was an investment of approximately 10 million euros.