GT-elements are regulatory DNA sequences ususally found in tandem repeats in the promoter region of many different plant genes. Depending on promoter structure, GT-elements can have a positive or a negative transcription function. The cognate GT-element binding factors contain one or two trihelix DNA binding motifs, which have so far been identified in plant transcription factors only. GT-factors are ubiquitously expressed; in Arabidopsis they belong to a small family of transcription factors. The functioning of plant GT-elements and GT-factors shows complex regulatory features of plant gene transcription.