Multiple myeloma (MM) remains incurable, largely owing to the lack of effective therapeutic targets. Wilms' tumor 1-associated protein (WTAP) has been implicated in MM tumorigenesis, but its underlying molecular mechanisms remain unclear. This study aimed to elucidate the role of WTAP in MM progression. Bone marrow samples from newly diagnosed MM patients were analyzed. WTAP expression was assessed via Quantitative real-time PCR (qRT-PCR) and Western blot. Cell proliferation was evaluated using EdU and flow cytometry assays, while RNA immunoprecipitation (RIP) confirmed protein interactions. WTAP was overexpressed in MM patients and correlated with poor survival. Its knockdown significantly suppressed MM cell proliferation and inflammation. RIP assays identified MAP6D1 as a potential WTAP target. RNA-seq analysis suggested WTAP regulates MM proliferation via the Hippo signaling pathway. WTAP promotes MM proliferation by targeting MAP6D1 and modulating the Hippo pathway, highlighting its potential as a therapeutic target.