Electronic Journal of Differential Equations, Vol. 2021 (2021), No. 11, pp. 1-17. Title: Existence of solutions for critical fractional p-Laplacian equations with indefinite weights Authors: Na Cui (Lanzhou Univ., Lanzhou, Gansu 730000, China) Hong-Rui Sun (Lanzhou Univ., Lanzhou, Gansu 730000, China) Abstract: This article concerns the critical fractional p-Laplacian equation with indefinite weights $$ (-\Delta_p)^su=\lambda g(x)|u|^{p-2}u+h(x)|u|^{p_s^*-2}u \quad \text{in }\mathbb{R}^N, $$ where $0sp$ and $p_s^*=Np/(N-sp)$, the weight functions g may be indefinite, and h changes sign. Specifically, based on the results of asymptotic estimates for an extremal in the fractional Sobolev inequality and the discrete spectrum of fractional p-Laplacian operator, we establish an existence criterion for a nontrivial solution to this problem. Submitted April 1, 2020. Published March 05, 2021. Math Subject Classifications: 35R11, 35J92, 35B33. Key Words: Fractional p-Laplacian; critical exponent; indefinite weight.