Glutathione S-transferases (GSTs) are well-known metabolic enzymes that play essential roles in the detoxification of a wide range of endogenous and exogenous compounds. In the present study, we identified a new GST gene in the destructive pest, Bactrocera dorsalis. The gene was found to cluster with the epsilon GSTs and was named BdGSTe10. BdGSTe10 contained an open reading frame of 669 nucleotides encoding a 222-amino acid protein. The predicted molecular weight and theoretical pI of BdGSTe10 were of 24.72 kDa and 5.40, respectively. The recombinant protein was expressed using a heterologous expression system, and its specific activity was found to be 304.07 nmol/min∙mg. During the development of B. dorsalis, BdGSTe10 was highly expressed in female adults with an increased expression on sexual maturation. Among the tissues of the vitellogenic stage, BdGSTe10 was highly expressed in the ovary. Silencing of the gene by feeding with gene-specific dsRNA suppressed BdGSTe10 expression by 69.24% and resulted in delayed development and reduced size of the ovaries. The ovaries of dsRNA treated females were all less than 1.4 mm in diameter, whereas 42.31% of the females in the control group had larger ovaries (> 1.4 mm). These findings demonstrate that this novel BdGSTe10 gene is functionally involved in ovarian development in B. dorsalis.