Three-dimensional (3D) cell cultures combining multipotent mesenchymal stromal cells (MSC), tendon extracellular matrix scaffolds, and mechanical stimulation by a bioreactor have been used to induce tenogenic differentiation in vitro. Yet, these conditions alone do not mimic the environment of acute inflammatory tendon disease adequately, thus the results of such studies are not representatives for tendon regeneration after acute injury. In this chapter, we describe two different approaches to introduce inflammatory stimuli, comprising co-culture with leukocytes and supplementation with the cytokines IL-1 β and TNF-α. The presented in vitro model of inflammatory tendon disease could be used to study musculoskeletal pathophysiology and regeneration in more depth.