Rotes Schloss Mihla, Renaissance castle in Mihla, Germany.

Rotes Schloss Mihla is a Renaissance castle in the Mihla municipality featuring a stone foundation supporting two half-timbered upper stories. The structure showcases three tower-like projections on its northern facade and a gable roof that completes its distinctive profile.

A Mainz electoral estate (Fronhof) stood here in the 13th century; the von Harstalls took it over after 1436. Hans David von Harstall had the present Renaissance castle built, completed in 1581, with a roof truss dated to that year. A 2009 building survey found Gothic doorways and Romanesque stone in the cellars, and later work around 1620 and 1730.

The name arose during construction and refers to the roof covering: unlike the Blue Castles of Mihla, the Rotes Schloss was roofed with red tiles rather than slate. The red tone was repeated in the timber frame, door ornament and window surrounds, set off against grey.

The castle has been vacant since 2004 and entry is prohibited due to structural damage. The exterior architecture and distinctive red brick appearance can be viewed from outside, allowing visitors to observe the building's character without interior access.

A 2009 building survey found that stones in the barrel vaults came from Romanesque-era construction, and Gothic doorways and niches were uncovered there. The same study identified seven building phases in the outbuildings along Eisfeldstrasse, the oldest far predating the 1580s.