With the advent of new technologies revolving around cement-based materials, such as 3D printing, there is a growing need for finer modelling of the material behaviour from the very early-age through to the hardened state, as well as adequate simulation strategies for the printing process itself. Considering various coupling mechanisms occurring in cementitious materials between mechanical, chemical, hydraulic and thermal phenomena, a precise description of the material behaviour is a challenging task. The mechanical behaviour of pastes at early age and its time evolution are paramount to the stability of objects built without formwork. The time evolution of the mechanical properties is controlled by the hydration kinetics, which depends greatly on the use of admixtures, as well as on temperature and relative humidity conditions. In the case of objects with high surface-to-volume ratio, as is typically the case with 3D printing, surface phenomena such as evaporation have important effects and should be taken into account. Herein, we present a framework for modelling mortar 3D printing processes, comprised of a general coupled thermo-hydro-chemo-poromechanical model for cement-based materials. The theoretical framework is based on the previous works in our group related to the development of a general modelling framework for oil-well cement pastes (Agofack,2020), based on an extensive experimental study (Ghabezloo,2008; Ghabezloo,2009; Ghabezloo,2010; Agofack2019}. The model has been implemented in a finite element analysis tool and its parameters have been evaluated for the printed material based on laboratory experiments. It is shown to be a valuable tool for simulation of the 3D printing process. Agofack, N., Ghabezloo, S., & Sulem, J. (2020). Chemo-poro-elastoplastic modelling of an oilwell cement paste: Macroscopic shrinkage and stress-strain behaviour. Cement and Concrete Research, 132(March), 106046. Agofack, N., Ghabezloo, S., Sulem, J., Garnier, A., & Urbanczyk, C. (2019). Experimental investigation of the early-age mechanical behaviour of oil-well cement paste. Cement and Concrete Research, 117, 91–102. Ghabezloo, S., Sulem, J., Guédon, S., Martineau, F., & Saint-Marc, J. (2008). Poromechanical behaviour of hardened cement paste under isotropic loading. Cement and Concrete Research, 38(12), 1424–1437.