No, subtraction is not associative.
Work Step by Step
If subtraction were associative, it would mean we could change the grouping, and the difference would not change. This is not the case. For example, $5-(3-2)=5-1=4$, but $(5-3)-2=2-2=0$. When we changed the grouping on the subtraction problem, the answer was different. Therefore, subtraction is not associative.