The 765LT Spider is the convertible version of the 765LT, the same hardcore Longtail derivative of the 720S, with a one-piece carbon-fiber Retractable Hard Top (RHT) in place of the fixed roof. Driven by eight electric motors, the roof raises or lowers in about 11 seconds at speeds up to ~50 km/h (~31 mph). It shares the coupé's 4.0-liter twin-turbo M840T V8 (755 hp / 765 PS), 7-speed dual-clutch gearbox and carbon tub, so performance is essentially identical despite the folding roof.

Revealed in July 2021 at $382,500 in the US, the Spider was deliberately capped at 765 units to match the coupé. Despite the roof mechanism it is quoted at only ~108 lb (~49 kg) heavier than the coupé (a DIN/curb ~3,060 lb / ~1,388 kg) and still around 176 lb (~80 kg) lighter than a 720S Spider. Notably, the Spider was excluded from the NHTSA 24V901000 rear-window recall that affected a slice of 2021 coupés.