Abstract: This paper reports the synthesis of Nd-doped strontium hexaferrite/rGO nanocomposites via a simple wet-mixing method. The nanocomposites were systematically investigated for their structural, morphological, thermal, and microwave absorption properties in the X-band frequency range. The successful formation of the nanocomposites was confirmed using various characterization technique including X-ray diffraction (XRD), Fourier-transform infrared (FTIR) spectroscopy, and Raman spectroscopy. Electron microscopy (SEM and TEM) revealed the microstructure and crystallographic features of the samples, confirming the uniform distribution of nanoparticles over the rGO sheets. The electromagnetic properties were measured using a vector network analyzer (VNA), where the nanocomposites were dispersed in an epoxy matrix with 50 wt% of SHF for measurement. The results demonstrated a significant enhancement in microwave absorption performance with increasing rGO content, attributed to the synergistic effects of magnetic loss from Nd-doped hexaferrite, dielectric loss from rGO, and interfacial polarization at the ferrite–rGO interfaces. Among the synthesized samples, 5% rGO loaded nanocomposite exhibited a minimum reflection loss of -25 dB at 9 GHz with an effective absorption bandwidth of 4 GHz at a thickness of 2.8 mm, covering nearly the entire X-band region and highlighting its potential as an efficient microwave absorbing material. This study utilized CST Microwave Studio to simulate the reflection and radar cross-section (RCS) of nanocomposites. The obtained simulated values closely aligned with experimental results, revealing a notable RCS reduction of approximately 9 dB for the 5% rGO nanocomposite. These findings validate the authenticity of the data and support the effectiveness of the simulation model.