Fiber-reinforced thermoplastic composite materials can find numerous applications in the transportation sector and replace thermoset composites. However, they have to comply with strict standards, particularly with those concerning their fire behavior. In this frame, composites based on an acrylic resin Elium ® (Arkema), a woven fiberglass, (taffetas tissue Chomarat G-Weave 600 P/A) and Exolit OP930 (Clariant) as fire retardant were prepared using three processes. The thermal stability and fire behavior was studied by means of thermogravimetric analysis and cone calorimetry. The obtained results allowed to highlight the drawbacks of each processing method and to select the most appropriate. The improvement of the fire behavior by combining post-curing of the composites, addition of a cross-linking agent and addition of aluminum trihydroxide (ATH) was also investigated.