Raman spectroscopy is widely used in drug development and delivery due to its label-free and non-destructive character. Reliable application to drug delivery systems requires unambiguous assignment of Raman bands from both the drug and the carrier material. Here, we establish the Raman spectral signatures of docetaxel (DTX)-loaded polymeric micelles (nanoparticles, NPs) based on Pluronic F-127, Soluplus, and a mixed Soluplus–TPGS system. DTX was nanoformulated to improve its aqueous solubility and therapeutic performance. In vitro FT-Raman measurements (1064 nm excitation) were performed on pure polymers, unloaded micelles, and DTX-loaded formulations. Detailed band assignments of the pure drug and nanocarriers were carried out and systematically compared with the loaded systems. Four characteristic DTX marker bands at 617, 1003, 1601, and 3072 cm−1 were clearly identified in Soluplus and Soluplus–TPGS nanoparticles, providing spectroscopic evidence of drug incorporation. Linear least-squares spectral decomposition enabled estimation of the relative Raman contributions of drug and carrier. The results demonstrate a higher loading capacity for Soluplus—TPGS mixed nanoparticles compared to pure Soluplus systems and establish a chemically rigorous Raman reference framework for future label-free studies of drug–polymer nanocarriers.