In the present work, the effect of the addition of potassium niobate (KNbO₃) nanoparticles (NPs) on the pinning properties of YBCO compound is investigated. The synthesis of YBCO:xKNbO₃ (x = 0–1 wt%) nanocomposites were carried out using a two-step process, firstly KNbO₃ NPs were synthesized via hydrothermal process, and later on, the nanocomposites were synthesized via solid-state reaction method containing various concentrations of NPs from 0 to 1 wt%. The effect of NPs of KNbO₃ in YBCO is studied using structural, morphological, transport, and magnetic measurements. From XRD spectra, the crystal structure of YBCO was found to be orthorhombic, which remained invariant even in the nanocomposites. Magnetic properties of YBCO and its nanocomposites over the range of − 6 T to + 6 T were characterized using magnetic property measurement system (MPMS). The Bean model is applied to calculate the critical current density (J_C), which has improved in YBCO:KNbO₃ nanocomposites as compared to YBCO. The maximum enhancement of ~ 4.4 times in J_C and pinning properties was found for YBCO:0.5wt%KNbO₃ nanocomposites due to the creation of defects in YBCO matrix. Additionally, it is observed that for nanocomposites compared to YBCO, the rate of J_C decay decreases with an increase of externally applied field, which indicates an enhancement in pinning properties of nanocomposites.