ABSTRACTCharacterizing co‐formulated monoclonal antibodies (mAbs) poses significant challenges in the pharmaceutical industry. Due to the high structural similarity of the mAbs, traditional analytical methods, compounded by the lengthy method development process, hinder product development and manufacturing efficiency. There is increasing critical need in the pharmaceutical industry to streamline analytical approaches, minimizing time and resources, ensuring a rapid clinical entry and cost‐effective manufacturing. This study investigates the application of process analytical technologies (PAT) to address such challenges. Our investigation introduces two complementary technologies, on‐line ultra‐performance liquid chromatography (online UPLC) and multimode fluorescence spectroscopy (MMFS), as potential PAT tools tailored for characterizing critical quality attributes (CQA) in co‐formulated mAb products. Specifically, the CQAs under evaluation include the total protein concentration of the mAbs within the co‐formulation and the ratio of mAb A to mAb B. Online UPLC enables direct and automated measurement of the CQAs through physical separation, while MMFS determines them in a non‐destructive and more swift manner based on chemometric modeling. We demonstrate these technologies' comparable performance to conventional methods, alongside substantial benefits such as reduced analytical turnaround time and decreased laboratory efforts. Ultimately, integrating them as innovative PAT tools expedites the delivery of therapeutic solutions to patients and enhances manufacturing efficiency, aligning with the imperative for swift translation of scientific discoveries into clinical benefits.