Glazing and window systems in New Zealand have been shown to be susceptible to significant damage as evidenced by the past decade of earthquakes. The seismic performance of glazing and window systems has resulted in considerable financial loss, disruption in business and physical injuries following earthquakes.  In order to investigate the vulnerability of residential windows in typical light timber framed buildings racking testing was conducted on six wall configurations.  Numerous observations of window performance were made during the testing and from these results fragility functions were developed for timber and aluminium framed windows.  These fragility functions suggest that even at low displacement levels damage can occur to windows that can potentially affect weather-tightness and require repairs following an earthquake.  These functions can inform decisions around designing for resiliency in residential structures in New Zealand.