Post-transcriptional regulation of gene expression is mediated in part by RNA binding proteins (RBPs). Roles for RBPs have emerged in the immune system but remain largely unexplored. My project utilised high-throughput genetic screens to identify roles for RBPs in lymphocytes. Initially, I generated custom sgRNA libraries targeting RBPs to facilitate CRISPR/Cas9 mediated gene knockout screens in either human or mouse contexts. Then, I employed these reagents to identify roles for RBPs in redox signalling, B cell lymphomagenesis, CD8 T cell activation, and B cell terminal differentiation. These identified over a dozen potential avenues of future investigation into the roles of RBPs in lymphocytes. I chose to further investigate the role of the RNA modification N6-methyladenosine (m6A) in B cells. This work demonstrated a role for the m6A binding protein Ythdf2 in promoting B cell terminal differentiation, independently of a role in proliferation or survival. In the future, I hope to validate an in vivo role for Ythdf2; and further elucidate the in vitro molecular mechanism.