Protein disulfide isomerase, containing thioredoxin (Trx) domains, serves as a vital enzyme responsible for oxidative protein folding (the formation, reduction, and isomerization of disulfide bonds in newly synthesized proteins) in the endoplasmic reticulum (ER). In this study, we identified TgPDI8, an ER-localized PDI protein in Toxoplasma gondii. Conditional knockdown of TgPDI8 resulted in a significant growth defect. To investigate the impact of TgPDI8 on protein expression, we assessed proteomic changes following the knockdown of TgPDI8.