Borate halides are an ideal materials class from which to design high‐performance nonlinear optical (NLO) materials. Currently, borate fluorides, chlorides, and bromides are extensively investigated while borate iodide materials discovery remains rare because of the perceived synthetic challenges. We report a new borate iodide, Pb2BO3I, synthesized by a straightforward hydrothermal method. The Pb2BO3I chemical formula conceals that the compound exhibits a structure similar to the well‐established KBe2BO3F2 (KBBF), which we show supports the highest second‐harmonic generation (SHG) at 1064 nm in the KBBF family, 10 × KH2PO4 (KDP), arising from the inclusion of Pb2+ and I− and the crystal chemistry. Our work shows that KBBF‐related compounds can be synthesized incorporating iodide and exhibit superior NLO responses. I've got my I on you: A new borate iodide, Pb2BO3I, is prepared for nonlinear optics applications by a straightforward hydrothermal method. It has a similar structure to KBe2BO3F2 (KBBF) and the highest second‐harmonic generation (SHG) in the KBBF family. Calculations show this SHG response arises from the inclusion of Pb2+ and I− ions.