Essential Work of Fracture (EWF) analysis was used to study the fracture toughness of a PETG film. In the study of the gauge length (Z) effect on the specific essential work (w(e)) using Z = 50, 100, 150, 200 and 250 mm, it is observed that w(e) is independent of gauge length, except that a slightly lower w(e) value was measured for Z = 50 mm. Interestingly, for specimens with long gauge lengths (Z greater than or equal to 150 mm in this study), brittle fracture occurred. The minimum ligament length at which ductile/brittle transition took place was observed to decrease with increasing gauge length. There is a small strain rate effect on w(e) with loading rates less than 1 mm/min. But with higher loading rates, w(e) showed no strain rate sensitivity.