In laser powder bed fusion of polymers (PBF-LB/P) flowability and packing properties are essential for powder spreading and resulting part properties. PBF powder requirements, structure-property relationships and appropriate methods for powder characterization will be discussed. Effects of particle size, particle shape and surface functionalization on flowability, packing density and tribo-charging will be addressed for different plastic powders, namely PA12 (virgin vs. aged), polyolefin and polyester powders. Dry particle coating as an efficient method to tailor powder flowability, bulk density and charging behavior is addressed. The capabilities of a ring shear tester, a powder tensile strength tester, a thermally controllable ring shear apparatus and a model experiment mimicking the powder spreading are demonstrated to assess PBF processability. Moreover, appropriate analytical methods for characterization of thermal and rheological properties and the resulting implications for processability are discussed.