TMIGD2 is a co-stimulatory immune receptor that is aberrantly expressed in human acute myeloid leukemia (AML) cells and is critical for the development and maintenance of AML and leukemia stem cells (LSCs). TMIGD2 promotes AML cell proliferation, blocks myeloid differentiation, and increases cell-cycle activity through the ERK1/2-p90RSK-CREB signaling pathway. Targeting TMIGD2 with anti-TMIGD2 monoclonal antibodies (mAbs) reduces LSC self-renewal and leukemia burden in AML patient-derived xenograft (PDX) models without affecting normal hematopoietic stem/progenitor cells. TMIGD2 is highly expressed in LSCs but not in normal hematopoietic stem/progenitor cells (HSPCs). TMIGD2 is essential for LSC maintenance and leukemogenesis but not for normal hematopoiesis. TMIGD2 is expressed on CD34⁺ AML cells and is co-expressed with CD45RA, CD123, and IL1RAP, which are LSC-specific markers. TMIGD2 knockdown significantly inhibits AML cell growth, induces apoptosis, and promotes myeloid differentiation. TMIGD2 is required for LSC self-renewal and leukemogenesis, but its function in normal HSPCs is minimal. Anti-TMIGD2 mAbs effectively target TMIGD2⁺ AML cells without affecting normal HSPCs, making TMIGD2 a promising therapeutic target for AML. The study highlights the role of TMIGD2 in LSCs and provides a new therapeutic strategy for AML.TMIGD2 is a co-stimulatory immune receptor that is aberrantly expressed in human acute myeloid leukemia (AML) cells and is critical for the development and maintenance of AML and leukemia stem cells (LSCs). TMIGD2 promotes AML cell proliferation, blocks myeloid differentiation, and increases cell-cycle activity through the ERK1/2-p90RSK-CREB signaling pathway. Targeting TMIGD2 with anti-TMIGD2 monoclonal antibodies (mAbs) reduces LSC self-renewal and leukemia burden in AML patient-derived xenograft (PDX) models without affecting normal hematopoietic stem/progenitor cells. TMIGD2 is highly expressed in LSCs but not in normal hematopoietic stem/progenitor cells (HSPCs). TMIGD2 is essential for LSC maintenance and leukemogenesis but not for normal hematopoiesis. TMIGD2 is expressed on CD34⁺ AML cells and is co-expressed with CD45RA, CD123, and IL1RAP, which are LSC-specific markers. TMIGD2 knockdown significantly inhibits AML cell growth, induces apoptosis, and promotes myeloid differentiation. TMIGD2 is required for LSC self-renewal and leukemogenesis, but its function in normal HSPCs is minimal. Anti-TMIGD2 mAbs effectively target TMIGD2⁺ AML cells without affecting normal HSPCs, making TMIGD2 a promising therapeutic target for AML. The study highlights the role of TMIGD2 in LSCs and provides a new therapeutic strategy for AML.