The Squamosa-promoter binding protein-like (SPL) genes represent a family of plant-specific transcription factors that are involved in the regulation a range of fundamental physiological and developmental aspects, such as grain development, the formation of plant architecture and panicle structure and stress responses. The present study aims to facilitate the functional genomics of TaSPL genes by comparing and utilizing the well documented SPLs’ functions in the monocot model specie, rice. Results have been made in the genome-wide characterization of TaSPLs: (1) 56 TaSPL genes were identified in common wheat (Triticum aestivum L.); (2) the orthologous relationships of TaSPLs with the corresponding OsSPLs were established; (3) the expression profiles of TaSPLs were compiled by analyzing several wheat RNA-seq datasets; (4) the function of TaSPL3-6A was analyzed by using the transgenic rice lines. Comparing the expression patterns of TaSPLs and OsSPLs, some TaSPLs appeared to exhibit the spatial-temporal expression patterns differing from the rice SPL orthologs, implicating the functional divergence between wheat and rice. Our expression analysis identified TaSPL2/6/8/10 to be responsive to several abiotic stresses and the phytohormone treatments, implying these genes as the candidate TaSPL members for the regulation of abiotic stresses. Additionally, transgenic lines of rice with ectopic expression of TaSPL3-6A headed earlier in both greenhouse and field environments, had shorter stems and narrower leaves, with altered panicle structures when compared with the wildtype control. In summary, we performed a comprehensive analysis of the SPL gene family between wheat and rice. Our work provides useful information toward better understanding of the functions of TaSPLs, emphasizes the conservation and divergence between TaSPLs and OsSPLs, and identifies the important SPL candidate genes for wheat improvement.