Automated tape laying is a well-established composite manufacturing process for high performance industries. While the process has seen vast growth over the 30 years of its conception, in-process monitoring is the most relevant and researched topic for present and future process development. The presented review highlights the importance of developing in-process monitoring tools and provides a detailed overview of such techniques for defect detection. Commonly occurring manufacturing defects, their influence on part and structural performance are assessed and discussed. The evolution of defect detection technologies considering defects types, accuracy, and speed are detailed. A summary of most promising approaches as per defect detection capabilities is presented. Defect rectification techniques are also discussed.