Update publication information. Aluminum (Al)-induced root tip cell elongation inhibition is a major cause of plant root elongation suppression. Root tip cell elongation inhibition is caused by disruption to cell wall component metabolism, growth signaling, or cellular damage. The aim of this study was to identify the proteins involved in root elongation under Al stress in the tolerant wheat (Triticum aestivum L.) ET8. We investigated wheat root protein profiles using isobaric tags for relative and absolute quantification (iTRAQ). In total, 97 differentially expressed proteins from Al-tolerant wheat roots were screened and 11 of the 97 proteins were root elongation related. The 14-3-3 protein, plasma membrane ATPase, phospholipase D, and peroxidase are involved in cell wall component metabolism. The cellulase activity and callase activity were down-regulated by Al stress, whereas, the PAL, CAD, and POD activities were up-regulated. In addition, the callose, cellulose, lignin, and H2O2 contents varied significantly. Furthermore, Al stress inhibited root elongation in a metabolic enzyme and carbohydrate-dependent manner. The results indicated that the protein involved with growth signaling is elongation factor 1-α. The cellular damage related proteins are glycosyltransferase and sucrose 1-fructosyltransferase. The iTRAQ analysis highlighted candidate proteins associated with root cell elongation and revealed several new aspects of the metabolic processes underlying Al toxicity and tolerance. We propose that Al stress leads to marked variations in metabolic enzyme activity, carbohydrate content, and cellular damage, followed by inhibition of root elongation in wheat roots. This study has provided the most integrated view of the adaptive root responses to Al-toxicity.