To simplify the expression \(3^{-3} \times 3^{-3}\), we can use the property of exponents that states \(a^m \times a^n = a^{m+n}\).
Thus,
\[ 3^{-3} \times 3^{-3} = 3^{-3 + (-3)} = 3^{-6}. \]
Now, looking at the multiple choice answers, the equivalent expression for \(3^{-6}\) is:
Option: \(3^{-6}\).
So the correct answer is \(3^{-6}\).