To find the y-intercept of the function \( g(x) = 5^x \), we need to evaluate the function at \( x = 0 \).
Calculating \( g(0) \):
\[ g(0) = 5^0 = 1 \]
Thus, the y-intercept of \( g(x) = 5^x \) is at the point \( (0, 1) \).
So the answer is:
\((0, 1)\)