In GaN e-HEMTs, Threshold Voltage $(\boldsymbol{V}_{TH})$ shift from gate voltage $(\boldsymbol{V}_{GS})$ stress depends on the $\boldsymbol{V}_{Gs}$ magnitude, stress time, recovery time (time between stress removal and $\boldsymbol{V}_{TH}$ measurement), temperature and pulse polarity (0 to $+\boldsymbol{V}_{GS}$ or $-\boldsymbol{V}_{GS}$ to $+\boldsymbol{V}_{GS}$). In this paper, unipolar (0 to $\boldsymbol{V}_{GS})$ and bipolar $(-\boldsymbol{V}_{GS}$ to $+\boldsymbol{V}_{GS})$ pulsed gate stresses have been performed on GaN e-HEMTs with different $\boldsymbol{V}_{GS}$ magnitudes. The pulse frequency ranges from 25 Hz to 200 kHz. The results show negative $\boldsymbol{V}_{TH}$ shifts for unipolar $\boldsymbol{V}_{GS}$ pulses (between 5V and 8V) at long recovery times (above 500 seconds). The $\boldsymbol{V}_{TH}$ shift is proportional to the $\boldsymbol{V}_{GS}$ pulse magnitude. When the recovery time is increased from 50 milliseconds to 500 seconds, the measured $\boldsymbol{V}_{TH}$ shift becomes more negative, indicating a faster release of trapped electrons than holes. In bipolar stresses, results show both positive and negative $\boldsymbol{V}_{TH}$ shifts with no clear magnitude or frequency dependencies.