Abstract: Some members of the plant-specific IQ67 domain (IQD) gene family coding a class of calmodulin-binding proteins play vital roles in regulating fruit shape. Investigation of IQD genes will help to improve fruit shape and promote yield in Camellia oleifera. Based on the genome data of C. oleifera, the IQD genes were identified, and the physicochemical properties and phylogenetic analysis of IQD proteins were analyzed. The expression of IQD genes in different tissues and in different cell clusters of mature ovaries in C. oleifera was analyzed using bulk transcriptome and single-cell RNA-seq data. A total of 48 CoIQD genes were identified, and the 48 CoIQD proteins were divided into 4 subfamilies and 9 groups according to the topology of phylogenetic tree. The CoIQD proteins distributed in groups I-1 and II-3 were more possible than ones in groups II-1 and IV-2 as candidate regulators of fruit shape. The results of expression profiling indicated that such 5 genes as CoIQD45/-47 of group I-1, CoIQD7/-14 of group II-3, and CoIQD27 of group II-1 expressed in both mature ovary and pericarp, and were candidate genes to regulate fruit shape. CoIQD7/-14/-47 were key candidate genes involved in regulating ovary height in C. oleifera.