Concrete is the most widely used construction material, however, concrete structures often suffer from poor durability and require frequent inspections and repairs. Concrete production is also associated with high carbon emissions and the large-scale depletion of natural resources. Recently, the addition of graphene nanoplatelets (GNPs) in cementitious materials has shown a potential to improve the performance and instigate additional functionalities. However, there is limited understanding around the environmental effects from the production of GNP and its incorporation in concrete. This study has investigated, by means of a Life Cycle Assessment (LCA), the environmental impact of concrete reinforced with graphene nanoplatelets by focusing on the “cradle-to-gate” of GNP production and their incorporation in concrete. The production of 1 kg of G2NanPaste (GNPs product) is found to result in 0.17 kgCO2 equivalent units which is lower than Portland cement (0.86 kgCO2 eq). Ordinary Portland cement (CEM I) is 248 times more damaging than G2NanPaste in terms of global warming. The superplasticiser addition is found to have a greater environmental impact compared to G2NanPaste. The sensitivity analysis showed that if the addition of GNPs results in a 5% reduction of the Portland cement, the effect of the concrete mix on global warming can be reduced by 21%. This indicates that GNPs could be environmentally friendly if used as a supplement for some of the cement. The main aim of this paper is to perform the first LCA of the addition of graphene nanoplatelets in concrete. It is hoped that this work will pave the way for further research in this area.