Multi‐walled carbon nanotubes (MWCNTs) with various aspect ratios were first designed onto the glass fiber fabric (Gf), for the purpose of fabricating a series of MWCNT–glass fiber fabric (MGf) composites with controllable interlaminar fracture toughness, adhesion and mechanical properties. The dispersal ability of MWCNT on the Gf surface was closely related to its aspect ratios, which may greatly affect the toughness and strength of epoxy‐based composites. An interesting result showed that the interlaminar fracture toughness of MGf composites with MWCNT aspect ratios of ~667 to ~1333 was significantly improved. Under an optimal MWCNT aspect ratio (~1333), the interlaminar shear, tensile and flexural strength of the MGf composite were raised by 43.8, 38.2, and 34.2%, respectively, and its dynamic mechanical properties had a similar rule, as compared with neat Gf composite. Almost all the MGf composites with MWCNT exhibited some ductile fracture behavior whether in tensile or flexural tests. POLYM. COMPOS., 40:E1329–E1337, 2019. © 2018 Society of Plastics Engineers