Variable-temperature Fourier transform infrared spectroscopy was used to investigate matrix–nanofiller interactions in amorphous semiaromatic polyamide/layered silicate nanocomposites prepared by melt intercalation. The types of polymer–nanofiller interactions were found to be strongly dependent on the nature of the polymer matrix and the surfactant-modified layered silicate. Improved compatibility resulted when hydrogen-bonding interactions occurred between the surfactant and polymer chains. The presence of surfactants with phenyl groups also led to a more stable molecular structure of the polymer matrix because of the enhanced resonance effect between aromatic groups. Si[BOND]O stretching vibrations in the layered silicate shifted to lower wavenumbers with increasing temperature; this indicated the presence of weaker polymer-layered silicate interactions. The results of this study demonstrate that for the polymer nanocomposites prepared by melting intercalation, more important interfacial interactions existed between the polymer and the surfactant.