In this article, we consider the following fractional (p, q)-Laplacian equation with critical exponent \(\begin{aligned} (-\Delta _p)^{s_{1}} u+(-\Delta _q)^{s_{2}} u=\lambda g(x)|u|^{r-2} u+h(x)|u|^{p_{s_{1}}^*-2} u \; \text {in}\; {\mathbb {R}}^N, \end{aligned}\) where \(0<s_{2}<s_{1}<1\) , \(1<q \le p<r< p_{s_{1}}^*\) and \(p_{s}^*:=\frac{ Np}{N-ps}\) for any \(s\in (0,1).\) Under certain assumptions on g et h, using an abstract critical point theorem, we obtain a multiple solutions for \(\lambda \) sufficiently large. A similar problem with subcritical exponents is also considered.