Aluminum (Al) toxicity in acid soil is one of the most severe environmental stress factors that limit world food production. Al ion (Al ³⁺ ) is highly reactive with negatively charged ligands of the cell and disturbs cell division and expansion at sub-micromolar levels. Since the harmful effects are caused by both cyto- and genotoxicities of Al, plant cells show various dose- and time-dependent responses. On the other hand, plants have evolved different Al tolerance strategies that protect sensitive cells from Al ³⁺ . These include restructuring of the cell wall to prevent deposition of Al ³⁺ and organic acid release by plasma membrane transporters to chelate out and exclude Al ³⁺ in the rhizosphere, regulated by the transcription factor STOP1 or its orthologs, and internal detoxification mechanisms including root-to-shoot translocation, antioxidant defense, and Al sequestration in vacuoles to prevent cytotoxicity. In recent years, genomics approaches, particularly genome-wide association studies and transcriptome analyses, have provided genetic evidence of well-known genes’ involvement in Al tolerance and uncovered new Al tolerance genes in plants. This chapter summarizes the findings from recent genomic studies that add to our understanding of the complex plant responses to Al toxicity.