Fused Filament fabrication (FFF), as one of most popular additive manufacturing method, is widely known with printing materials such as Polylactic acid and ABS. Due to their relatively low mechanical properties, these materials do not meet the high standard of materials for aerospace applications. With the gain of popularity of the additive manufacturing, reinforced Polyetheretherketone (PEEK) composites represents promising source of 3D printing material. However, the use of this high temperature resistant thermoplastic can be challenging. The main difficulty in forming PEEK part by using FFF is the high melting temperature of PEEK. Different printing parameter must be taken in consideration to reduce known structures problems such as stress, warpage and delamination. In this study, the 3D printability and the mechanical properties of PEEK composites are investigated. Filament spools for 3D printing of PEEK composites were manufactured using a semi-industrial scale extruder. 3D printing was performed using an AON3D, a printer equipped with a heat chamber particularly suited to high temperature thermoplastics and a nozzle module which is able to reach PEEK melting temperature. Several structures have been printed: standard dogbone samples for mechanical tensile test, complex structures (e.g. octopus, aircraft prototypes components, etc.). The mechanical test results showed that the optimization of the printing parameter is strongly related to the quality of a printing piece. The material showed a good printability which proves that this kind of composite for 3D printing could find its place in engineering application such as aerospace or automobile.