Organizations have shown a significant interest in adopting human and communication-oriented agile practices for Global Software Development (GSD). Agile practices originated in the context of small and medium co-located project teams present a number of communication challenges when they are applied to the distributed GSD. There is a need to understand the underlying communication challenges of agile GSD environment. This paper adopts a Systematic Literature Review (SLR) approach and reports communication challenges in the agile GSD context. A customized literature search and selection criteria was first developed and then applied to initially identify a set of 449 papers. Finally, 22 of 449 papers, relevant to this research, were selected for this study. These final 22 papers were reviewed and 7 major categories of communication challenges were identified in the context of agile GSD. The review results of this paper are expected to help researchers and practitioners to understand communication challenges of agile GSD and develop tools, techniques and strategies to deal with these challenges. This paper is limited to the number of reviewed studies from selected databases.