Glass fibre-reinforced epoxy (GFRE) composites have had limited use as structural components in industrial applications (e.g., oil and gas, aerospace and civil infrastructure). The use of nanomaterials, such as graphene, has been explored recently to enhance the mechanical and long-term properties of GFRE to realise their full potential and increase their usage. This study evaluated the tensile, creep, and fatigue behaviour of amine-functionalised graphene oxide (fGO) modified glass fibre/epoxy laminate composites. A spray coating technique was used to coat the fGO particles onto the glass fibre surface, and epoxy composite laminates were manufactured using the vacuum resin infusion method. Creep and fatigue testing was performed under a load-controlled mode in tension. Adding fGO within the composites significantly improves the static, creep, and fatigue properties of the fGO-GFRE composites at both room and elevated temperatures. It is shown that fGO acts as a barrier to microcrack initiation and restrains the macrocrack propagation during cyclic loading under elevated temperatures in the GFRE composites. These factors, therefore, prevent the early delamination of the matrix and fibre interface during cyclic loading, which explains the fatigue life extension observed in the fGO-modified composites. With 0.05 wt% fGO, the fatigue life of the fGO-GFRE composites was extended by 8× and 30× at a maximum stress of 124 and 151 MPa respectively, in a 90 °C environment compared to the control GFRE composites. While the creep life compared to the control increased by 63×, 103× and 159× with 0.25 wt%, 0.5 wt% and 1 wt% fGO, respectively. These enhancements are attributed to the large surface area, high stiffness, and functional groups present, which provide a stronger bond between the composite phases. These features help restrict the mobility of the polymer chain during the creeping load and act as barriers to fatigue crack propagation, enhancing the composite’s durability. The nanocomposites produced display attractive properties for many possible industrial applications where improved performance is needed while maintaining a minimum cost.