Lightweight rubberized geopolymer (LRGP) has gained attention due to its economic, engineering, and environmental benefits. With the rising human demands, the need for alternative materials to meet the requirements of infrastructural expansion, and global industrialization required. Based on those facts, this study aimed to develop of lightweight geopolymer mortars using wastes rubber as fine aggregate (WRA) to replace the natural aggregates, which metakaolin (MK), wastes bottle glass (WBG) and granulated blast furnace slag (GBFS) used as precursor materials with alkaline activator contained low molarity of sodium hydroxide solution and sodium silicate and cured at ambient temperatures. The effect of WRA on physical, mechanical, and microstructural properties of metakaolin-based rubberized geopolymer has been evaluated by using several tests such as compressive, flexural and tensile strength. As well as morphology and chemical reaction on LRGP by using AFM, FESEM, EDX, FTIR and XRD tests. In addition, a sustainable shape design has been cast and subjected to compressive strength to obtain the strength performance of the proposed LRGP mortar. At optimal mixture, the SEM images exhibited improvement in the interfacial transition zone (ITZ) among WRA and binder, leading rubberized geopolymer with 15% WRA to achieve a strength of 27.47 MPa after 28 days and with a reduction in density by 7.2%. The findings of this study can provide valuable insights on utilizing WRA in the shape design and formulation of geopolymer mortar, a key ingredient in the development of functional environmentally friendly building materials.