In plants, ubiquitin and small ubiquitin-like modifier (SUMO) are related small proteins which are members of the large ubiquitin superfamily of post-translational modifiers. The ubiquitinated proteins are destined to 26S proteasome for degradation, whereas SUMO-conjugated (SUMOylation) proteins influence numerous cellular processes such as plant’s responses to abiotic stress such as heat, drought, salinity, etc. In rice, SUMO E3 ligase gene OsSIZ1 has been shown to play an important role in plant response to abiotic stresses; loss of function of OsSIZ1 leads to increased sensitivity to drought, heat and salt stresses. Using full length cDNA and protein sequences of OsSIZ1 gene as reference, putative orthologs of SIZ1 were identified in eight monocot and two dicot species. The sequence similarity at cDNA level ranged from 78.81 to 82.6% in monocots and 58.25% to 59.5% in dicots. The coding DNA sequence (CDS) similarity ranged from 78.25% to 85.57% in monocots and 60.48% to 63.25% in dicots. Protein sequence similarity ranged from 44.78% to 81.27% in monocots and 47.9% to 52.99% in dicots. Among all the species, 10 distinct motifs belonging to SIZ1 were identified; eight were novel and two were reported in previous studies. The SIZ1 proteins were characterized by a single conserved domain belonging to PHD-Bye1p-SIZ1-like domain present in all the monocots and dicots. Quantitative real-time polymerase chain reaction (qRT-PCR) analyses revealed that SIZ1 transcripts were significantly upregulated in wheat seedlings under 6 h heat stress. Two heat tolerant wheat genotypes (Giza168 and IC2538749) showed significant up regulation (>2-fold change) as compared to the two heat sensitive wheat genotypes (PBW343 and HD2967), which showed non-significant up-regulation. Thus, findings of this study provide evidence for conservation of SIZ1 gene in different monocot and dicot species and the expression pattern of TaSIZ1 gene lays the foundation for further research related to heat tolerance breeding in wheat.