The Toyota Avanza and Daihatsu Xenia are a series of multi-purpose vehicles (MPV) developed by Daihatsu and marketed by both Toyota and Daihatsu, mainly sold with three-row seating. The Avanza and Xenia were developed as an entry-level MPV marketed mainly for the Indonesian and other emerging markets, and mainly produced in Indonesia by Astra Daihatsu Motor. Avanza's spiritual predecessor was the Kijang, whose model program has since been split into two different models (the other being the larger Kijang Innova) to expand Toyota's reach in the MPV sector.

In addition to Indonesia, the Avanza is sold throughout Southeast Asia, Mexico, Pakistan, Nepal, Bangladesh, Sri Lanka, the Middle East, Caribbean, Egypt, South Africa and other various African countries. A rebadged version of the car was sold in China under the FAW badge until 2016.

In 2021, the Avanza spawned another twin model called the Toyota Veloz, which the "Veloz" name was previously used for Avanza's flagship grade level for some markets between 2011 and 2021. The Avanza also served as a basis for the second-generation Perodua Alza, which was introduced in Malaysia in 2022.

The Avanza was the best-selling passenger car in Indonesia between 2006 and 2019, and then in 2021. At the peak of its popularity in 2013, the Avanza made up 17 percent of total car sales in Indonesia (22 percent combined with the Xenia). By November 2018, around 2.75 million units of Avanza/Xenia had been sold globally.

The name Avanza is derived from the Spanish word avanza which means 'get moving' and the Italian word avanzato, which means 'advance'. The name Xenia is derived from the Greek term Xenia, a concept of hospitality. The name Veloz is taken from the Spanish word veloz, meaning 'fast'.

The Avanza and Xenia were both conceived by Toyota, Daihatsu and its Indonesian subsidiaries in the wake of the 1997 Asian financial crisis. At the time, the price of the best-selling Kijang had skyrocketed, while the economy in the country had just recovered from the crisis. Feasibility studies started in 1999 when Toyota-Astra Motor proposed for a more affordable vehicle under the Kijang for the Indonesian market. Toyota Motor Corporation handed the development and manufacturing of the vehicle to Astra Daihatsu Motor due to Daihatsu's expertise on low-cost vehicles in Indonesia. Toyota and Daihatsu invested a total of US$90,000,000 for the project.

The project was also referred by Toyota as the U-IMV (Under-IMV) project, a reference to the Innova that sits in a segment above the Avanza which rides on the IMV platform. Unlike the Kijang and the succeeding Kijang Innova that both utilised full body-on-frame chassis, the first two generations of Avanza/Xenia used a semi-unibody chassis where the front half of the chassis used body-on-frame construction, while the rear half used monocoque construction. This hybrid-type chassis made it possible for the vehicle to retain the rear-wheel-drive layout from the previous generations of Kijang along with its ability to handle heavier loads. According to journalists, it also came with several downsides such as unstable ride during high speeds and unrefined NVH levels.

The second-generation model retained the same platform as the original model and took 4 years of development. Toyota and Daihatsu invested Rp 900,000,000,000 for the project.