To simplify the expression \( 125^{2/3} \), we can first rewrite \( 125 \) as a power of \( 5 \):
\[ 125 = 5^3 \]
Now substituting this into our expression:
\[ 125^{2/3} = (5^3)^{2/3} \]
Using the property of exponents \((a^m)^n = a^{m \cdot n}\), we can simplify:
\[ (5^3)^{2/3} = 5^{3 \cdot (2/3)} = 5^2 \]
Now, \( 5^2 \) can be expressed as a product of identical factors:
\[ 5^2 = 5 \cdot 5 \]
Therefore, the simplified form of \( 125^{2/3} \) is:
\[ \boxed{5 \cdot 5} \]