The CCR4-NOT complex is a conserved eukaryotic deadenylation machinery that plays essential roles in post-transcriptional regulation of mRNA metabolism, embryonic development, and reproduction. However, the composition and expression dynamics of the CCR4-NOT complex subunits in marine mollusks remain unexplored. Here, we systematically identified nine CCR4-NOT complex subunits in the Pacific oyster Crassostrea gigas. Phylogenetic and domain analyses revealed all CNOT proteins retained subtype-specific structural features in C. gigas. Notably, the oyster genome encodes CNOT7 but lacks CNOT8, consistent with the distribution observed in the analyzed invertebrates. Developmental expression profiling revealed typical maternal transcript expression patterns for six Cnot genes. Tissue-specificity analysis identified Cnot7 as the only Cnot gene meeting the predefined criterion for gonad-specific expression. Single-nucleus transcriptomic analysis further showed it was preferentially expressed in the oocyte lineage, with the highest expression in mature oocytes. These findings provide a molecular characterization of the CCR4-NOT subunits in a marine bivalve, and identify Cnot7 as a germline-associated candidate subunit potentially involved in reproductive development and early embryogenesis in C. gigas.