Aluminum (Al) is the most abundant metal in the Earth's crust, and its toxicity to plants is significant, especially in acid soils. Al toxicity primarily affects root growth, which is inhibited within 60 minutes of exposure to micromolar concentrations of Al. The primary sites of Al toxicity are the root apices, where Al accumulation and physical damage are more pronounced. Al toxicity can be influenced by its interaction with calcium (Ca), as Al can inhibit Ca uptake and displacement of Ca from the apoplast. Al-tolerant plants, such as wheat, have mechanisms to exclude Al from root apices, including the efflux of malate, which chelates and detoxifies Al. Recent studies have identified genes and proteins involved in Al tolerance, such as the *Alt1* locus in wheat, which codes for a malate-permeable channel responsive to Al. Future research should focus on developing techniques to detect Al uptake into different cellular compartments and cloning Al-tolerance genes to better understand the mechanisms of Al tolerance in plants.Aluminum (Al) is the most abundant metal in the Earth's crust, and its toxicity to plants is significant, especially in acid soils. Al toxicity primarily affects root growth, which is inhibited within 60 minutes of exposure to micromolar concentrations of Al. The primary sites of Al toxicity are the root apices, where Al accumulation and physical damage are more pronounced. Al toxicity can be influenced by its interaction with calcium (Ca), as Al can inhibit Ca uptake and displacement of Ca from the apoplast. Al-tolerant plants, such as wheat, have mechanisms to exclude Al from root apices, including the efflux of malate, which chelates and detoxifies Al. Recent studies have identified genes and proteins involved in Al tolerance, such as the *Alt1* locus in wheat, which codes for a malate-permeable channel responsive to Al. Future research should focus on developing techniques to detect Al uptake into different cellular compartments and cloning Al-tolerance genes to better understand the mechanisms of Al tolerance in plants.