Glass fiber reinforced polyethylene pipes (GFRPs) are increasingly utilized in the oil and gas transportation industries because of their various benefits. Delamination is one of the most common defects in GFRPs during manufacturing and service, which can affect their mechanical properties. This paper focused on the influence of delamination on short-term burst strength of GFRPs. The GFRPs specimens were 100mm-inner diameter and reinforced by 12 layers of ± 55° cross winding glass fiber tapes. Firstly, artificial delamination of different widths were designed and put into the specimens. Then, the short-term burst tests were carried out. Meanwhile, finite element models were established to predict the burst pressures and the numerical results were in good agreement with that of test results. The results showed that the widths and axial locations of delamination defects had significant influence on the burst pressure and stress distribution, which could lead to a premature burst failure of GFRPs during service. The deformation of GFRPs close to the defect region was also analyzed and the failure mechanism of GFRPs containing defects was discussed in detail.