Among the flaviviral proteins, NS5 is the largest and most conserved. NS5 contains major enzymatic components of the viral replication complex. Disruption of the common key NS5-host protein-protein interactions critical for viral replication could aid in the development of broad-spectrum anti-flaviviral therapeutics. To this end, we investigated the JEV- and ZIKV-NS5 interactomes in human cells using GFP pull-downs with mass spectrometry analysis in a label-free fashion. A total of 138 cellular proteins interacting with NS5 from JEV, ZIKV, or both were identified as Protein classification analysis of identified cellular targets revealed the enrichment of RNA binding, processing and splicing including spliceosomal and spliceosome-associated proteins in both datasets. Comparison of our data with literature not only revealed several cellular NS5 interacting proteins shared among flaviviruses, but also identified proteins that have no known function in flavivirus biology such as RNA polymerase II-associated Paf1 complex, protein phosphatase 6, and s-adenosylmethionine synthetase. Our study generates the first landscape of the JEV and ZIKV NS5 interactome in human cells and identifies cellular proteins that are potentially targetable for broad-spectrum anti-flaviviral therapy.