Another work reported that the addition of glass fibers to PP filaments can be an option for parts used in the automotive industry, indicating that they can significantly improve the energy absorption capacity, which is attributed to the textile architecture that is formed and allows it to withstand higher loads in different directions [16]. Another type of fiber that has been studied as a reinforcement in thermoplastic polymers is carbon fiber; it was found that 3D-printed parts with carbon fiber showed greater resistance to failure due to a good interaction with the polymer matrix [18]. Rice husk is a waste product that has been used as a reinforcement in polymers for filaments for the 3D printing process; research has found that the tensile strength of this r-PP is lower, a behavior that can be attributed to a weak interfacial attraction between the polymer and the particles [19]. Another type of lignocellulosic material that has been studied as a reinforcement in PP is cocoa shell, which was found to decrease the thermal stability of PP; in addition, the crystallization and fusion processes were affected by the addition of this type of particle, but the mechanical properties increased depending on the printing conditions, such as the loading direction and raster angle, among other conditions [20]. Inorganic particles such as CaCO\({}_{3}\) have also been added to PP to obtain PP composite filaments [21]. Some commercial filament polymers, such as buta-1,3-diene;prop-2-enenitrilestyrene (ABS), poly (vinyl acetate) (PVA), polycaprolactone (PCL), and nylon, are available [22]. One of the most studied polymers for 3D printing is poly (lactic acid) (PLA) [23], and some other composites have been reported. PLA-based composites with almond shell particleswere shown to have improvements in mechanical properties, such as shore D hardness, Young's modulus, and compression, which indicated that these properties depend on the printing pattern [24]. Among the most commonly reported polymer matrices in composites for 3D printing, PP is a widely used polymer due to its properties such as easy processing and low density [25]. Several works report the reinforcement of PP with natural fibers, such as wheat straw, bagasse, sunflower stems, and corn husks [26; 27; 28]. Garlic husk (GH) is a lignocellulosic waste material obtained from garlic seeds and is widely used in the food industry as a spice, as a vegetable coating, for the extraction of antioxidants, and for the extraction of contaminants in water [29; 30; 31]. However, research on the use of this waste material as a polymer additive is lacking. Our group reported the use of garlic husk particles (GHPs) in thermoplastic composites with interesting results, mainly in relation to the thermal properties, which were improved in comparison with those of pristine PP [32; 33]. Considering the growing interest in the use of lignocellulosic waste as an additive in thermoplastic polymers and the fact that the use of PP filled with garlic husk particles (GHPs) in 3D printing is unexplored, the present work reports the use of GHPs as a reinforcement in a PP matrix to obtain composite PP-GHP filaments with different contents, all of which were developed using a single extrusion. The filaments were used to obtain 3D-printed composite specimens, whose thermal properties were evaluated using thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and dynamic mechanical analysis (DMA). X-ray diffraction (XRD) was also carried out to evaluate the crystallinity of the 3D-printed specimens. The aim was to obtain a sustainable material and find industrial applications for lignocellulosic waste materials such as GHPs. The results obtained herein for the thermal stability, thermal behavior, and viscoelastic properties are discussed.