A functional central limit theorem is obtained for a stationary linear process of the form $X_{t}= sumlimits_{j=0}^infty{a_{j}x_{t-j}}$, where {x_t} is a strictly stationary sequence of negatively associated random variables with suitable conditions and {a_j} is a sequence of real numbers with $sumlimits_{j=0}^infty|a_{j}|