By definition, gas-lift valves (GLVs) are designed to allow influx of the annular gas into the tubing and prevent any backflow, even when there is a pressure differential toward the annulus. However, elements such as erosion, corrosion, scale, fatigue, vibration, and temperature and pressure effects may cause the GLV to leak, thereby posing a serious safety issue. Because of the well integrity concern, suspected GLVs are often retrieved for inspection with a wireline from the side-pocket mandrel. Proactive testing is a way to minimize such costly intervention. This paper presents simple models for analyzing transient-pressure data that is gathered at the casinghead during integrity testing of the GLV under various conditions. Field data were used to validate the models. While direct validation of the model was not feasible for all test modes, the liquid-level data during acoustic well-sounding tests largely validated the model. Our analyses also pointed to the possibility of designing simpler tests to assess the GLV integrity. Specifically, we reached the following conclusions: (1) Newly developed interpretative models allow estimation of leakage rate from both drawdown and buildup tests of the annular gas, which have been indirectly verified for three wells. In this context, the current practice of gathering liquid-level data by acoustic well sounding can be avoided, largely because only the liquid intrusion is expected to occur in a gas-lift well. (2) The proposed two-step approach to data gathering (i.e., drawdown and buildup of the annular gas after the well shut-in) shortens the total test duration, thereby reducing the expense considerably.