<p>Flame retardant agents from carbon nanotubes (CNTs) have become a great interest by researchers to be used in polymer materials for improvement in flame retardancy. However, the excellent properties as a flame retardant barrier exhibited by CNTs are restricted by the dispersion issue and become a main challenge to overcome. Due to this, CNTs tend to form agglomeration and turn into crystalline bundles due to the strong van der Waals force. In order to get uniform CNT dispersion, the interfacial bonding compatibility between CNTs and matrices needs to be studied, which provides a better guide for flame retardant capability. The modification of CNTs is one of the areas that needs to be discussed. In this review paper, we focused on CNT extraction, modification, and its properties on flame retardant performance when combined with polymer composites. Different synthesis routes have been used and discussed properly, such as electric-arc discharge, laser ablation, and chemical vapor deposition for CNT extraction. The modification through covalent bonds on single- and multi-walled carbon nanotubes has been the main focus for changing the polarity of CNTs. Due to the stability of graphene as a single layer of CNT, most of the studies use graphene as the main material for improving the thermal and flammability properties. The flammability properties and heat resistance of polymer carbon nanotubes were studied using limiting oxygen index (LOI), UL-94 test, and cone calorimetry. Furthermore, the flame retardancy performance within different polymer matrices with CNTs was also briefly studied and compared.</p>