The adoption of fiberglass-reinforced polymer (FRP) pipelines in industries such as oil, gas, water, and sewage has surged in recent years. FRP is favored as an alternative to metallic pipelines due to its superior characteristics like corrosion resistance, reduced weight-to-strength ratio, and customizable properties. However, their complex manufacturing and specific handling processes render them vulnerable to various defects. Moreover, the heterogeneity and anisotropic nature of FRP composites further exacerbate the challenge of defect identification and detection. This study presents a comprehensive review of defects observed in FRP pipelines, drawing insights from the academic literature. The paper systematically classifies these defects based on their occurrence during the pipeline’s lifecycle: manufacturing, storage and installation, and in-service stage. As FRP pipes continue to gain traction in the industry, this review aims to provide industry professionals, researchers, and pipeline operators with a consolidated understanding of the potential defects in FRP pipelines, paving the way for improved quality control and pipeline longevity. In addition, the study underscores that the development of non-destructive testing (NDT) techniques for FRP pipelines is in its infancy, emphasizing an attractive avenue for further research and technology development in this realm.