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Respiratory burst oxidase homologs (Rbohs) are critical enzymes involved in the generation of reactive oxygen species (ROS) that play an important role in plant growth and development as well as various biotic and abiotic stresses in plants. Thus far, there have been few reports on the characterization of the <i>Rboh</i> gene family in <i>Citrus</i>. In this study, seven <i>Rboh</i> genes (<i>CsRbohA</i>~<i>CsRbohG</i>) were identified in the <i>Citrus sinensis</i> genome. The CsRboh proteins were predicted to localize to the cell membrane. Most CsRbohs contained four conserved domains, an EF-hand domain, and a transmembrane region. Phylogenetic analysis demonstrated that the CsRbohs were divided into five groups, suggesting potential distinct functions and evolution. The expression profiles revealed that these seven <i>CsRboh</i> genes displayed tissue-specific expression patterns, and five <i>CsRboh</i> genes were responsive to cold stress. Fourteen putative <i>cis</i>-acting elements related to stress response, hormone response, and development regulation were present within the promoters of <i>CsRboh</i> genes. The in-silico microRNA target transcript analyses indicated that <i>CsRbohE</i> might be targeted by csi-miR164. Further functional and physiological analyses showed that the knockdown of <i>CsRbohD</i> in trifoliate orange impaired resistance to cold stress. As a whole, our results provide valuable information for further functional studies of the <i>CsRboh</i> genes in response to cold stress.