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The STAY-GREEN (SGR) proteins play an important role in chlorophyll (Chl) degradation and are closely related to plant photosynthesis. However, the availability of inadequate studies on SGR motivated us to conduct a comprehensive study on the identification and functional dissection of SGR superfamily members in kiwifruit. Here, we identified five <i>SGR</i> genes for each of the kiwifruit species [<i>Actinidia chinensis</i> (Ac) and <i>Actinidia eriantha</i> (Ae)]. The phylogenetic analysis showed that the kiwifruit <i>SGR</i> superfamily members were divided into two subfamilies the SGR subfamily and the SGRL subfamily. The results of transcriptome data and RT-qPCR showed that the expression of the kiwifruit <i>SGRs</i> was closely related to light and plant developmental stages (regulated by plant growth regulators), which were further supported by the presence of light and the plant hormone-responsive <i>cis</i>-regulatory element in the promoter region. The subcellular localization analysis of the AcSGR2 protein confirmed its localization in the chloroplast. The Fv/Fm, SPAD value, and Chl contents were decreased in overexpressed <i>AcSGR2</i>, but varied in different cultivars of <i>A</i>. <i>chinensis</i>. The sequence analysis showed significant differences within AcSGR2 proteins. Our findings provide valuable insights into the characteristics and evolutionary patterns of <i>SGR</i> genes in kiwifruit, and shall assist kiwifruit breeders to enhance cultivar development.