This document specifies the characteristics of lightweight aggregates (LWA) and LWA fillers and mixtures of them intended to be used in concrete, mortar and grout, bituminous mixtures, surface treatments and for unbound and hydraulically bound applications in construction works. This document covers LWA and LWA fillers from mineral materials having particle densities less or equal to 2000kg/m3 (2,000Mg/m3) or loose bulk densities less or equal to 1200kg/m3 (1,200Mg/m3). With regard to the aggregate size, this document covers LWA: fine lightweight aggregate (see 3.1.7), coarse lightweight aggregate (hereafter called coarse LWA) (see 3.1.8), all-in lightweight aggregate (hereafter called all-in LWA) (see 3.1.9) and LWA fillers (see 3.1.10). With regard to the material source and production technique, this document covers LWA and LWA fillers: of natural origin (see 3.1.2), manufactured from natural materials (see 3.1.3), manufactured from by-products of industrial processes (see 3.1.4) or from recycled source materials (see 3.1.5), and as by-products of industrial processes (see 3.1.4). Limits given to densities are related to some test methods which might not be applicable to some lightweight aggregates and lightweight aggregate fillers. This limitation is purely based on technical reasons and not to exclude any products from the market. This document also specifies procedures for assessment and verification of constancy (AVCP) of performance of characteristics of LWA and LWA fillers. This document does not cover LWA and LWA fillers of recycled aggregates from construction and demolition waste and Municipal Solid Waste Incinerator Bottom Ash (MIBA) (covered by prEN17555‑1:2021).