ABSTRACTWhile polyetherketoneketone is a high‐performance thermoplastic polymer, its hydrophobicity and inertness limit bone adhesion. This study aimed to evaluate a novel PEKK/CaSiO3/TeO2 nanocomposite, comparing it to PEKK/15 wt.% CaSiO3 and PEKK groups. The in vitro study, involving 90 discs (n = 30), assessed the cytotoxicity of all groups after 24, 72, and 168 h. The in vivo animal study, using cylinder‐type implants (n = 30), evaluated osseointegration through biomechanical push‐out tests, descriptive histopathological examinations of decalcified sections stained with hematoxylin and eosin, and histomorphometric analysis of new bone formation area after 2‐ and 6‐week healing intervals. The cytocompatibility of PEKK/15 wt.% CaSiO3/1 wt.% TeO2 composite confirmed its acceptance as a biomedical material. Additionally, in vivo study results showed that the PEKK/15 wt.% CaSiO3/1 wt.% TeO2 had the highest shear strength value and the highest new bone formation area compared to other experimental groups. The multimodal concept of adding CaSiO3 micro fillers and TeO2 nanofillers to PEKK produces a cytocompatible composite that enhances osseointegration and new bone formation in a rabbit's femur after 2‐ and 6‐week healing intervals.