To solve \( 3^{-4} \), we can apply the Property of Negative Integer Exponents, which states that \( a^{-n} = \frac{1}{a^n} \).
Using this property, we have:
\[ 3^{-4} = \frac{1}{3^4} \]
Next, we calculate \( 3^4 \):
\[ 3^4 = 3 \times 3 \times 3 \times 3 = 81 \]
Now substituting this back in, we get:
\[ 3^{-4} = \frac{1}{81} \]
Thus, the answer is:
\[ \frac{1}{81} \]