Timber buildings have been preferred in many regions for the sustainable nature of timber material. Although engineered timber products become promising alternates to traditional construction materials, the fire safety of timber buildings remains a key barrier to wider use. Currently, the design of timber structures mostly adopts the Eurocode 5 approach, which estimates the heat transfer or char depth under the premise of standard fire exposure. To investigate the behaviour of timber structural members in the context of realistic fire action in compartments, appropriate models for different stages of numerical simulation are needed. A series of development have now been conducted in the open‐source platform OpenSees, which enables modelling the heat transfer of timber sections in non‐standard fire scenarios and thermo‐mechanical analysis model using either beam elements or shell elements for various timber structural members. Corresponding thermal actions are developed to deal with timber slabs in fire or timber beams subjected to three‐side fire exposure. Tests on cross‐laminated timber beams at ambient temperature and under fire exposure are modelled to validate the developed capabilities, which is followed by modelling a glued laminated timber beam heated by furnace. In the end, a timber‐concrete composite slab is modelled using the fire impact from a Computational Fluid Dynamics model, which demonstrates the current vision of modelling timber structures in fire and OpenSees for fire is committed to providing such an open‐source research platform to support further modelling work.