Polyetherimide (PEI) has recently been used in additive manufacturing as it possesses excellent mechanical and thermal properties. These properties have led to its applications across industries including aerospace, automotive and medical industries. The use of high-performance polymers (HPP) poses attractive properties in relation to medical devices, however, concerns remain with respect to bioactivity. Addition of bioactive fillers to mitigate against this has been considered, such as hydroxyapatite (HA), the main mineral component of human bone. This study considers the preparation and characterisation of PEI-based filaments containing 10, 20, and 30 wt.% of HA and then subsequently printed using fused filament fabrication (FFF). Mechanical, thermal and morphological analysis was performed. Bioactivity was investigated via immersion in simulated body fluid (SBF). PEIHA-20% was recognised as optimal for maintaining acceptable tensile strengths of a mean value of 56.4 MPa and improving Youngs modulus beyond the neat value to a value of 1683 MPa. Scanning electron microscopy (SEM) and SEM- energy dispersion X-rays (EDX) confirmed apatite formation through the detection of calcium and phosphorus elements on the top surface of the samples after 7 days of immersion. Although, mechanical properties are reduced, bioactivity is induced, with values within the threshold for cortical bone/implantable material.