Mesenchymal stem cells (MSCs) are one of the main residents in the bone marrow (BM), having an essential role in the regulation of hematopoietic stem cell (HSCs) differentiation and proliferation. Myelodysplastic syndromes (MDS) are a group of myeloid disorders impacting hematopoietic stem and progenitor cells (HSCPs) and characterised by BM failure, ineffective haematopoiesis, cytopenia, a high risk of transformation through the expansion of MDS clones together with additional genetic defects. It has been indicated that MSCs play anti-tumorigenic roles such as cell cycle arrest and pro-tumorigenic roles including induction of metastasis in MDS and leukaemia. Growing evidence has shown that MSCs have impaired functions in MDS, such as decreased proliferation capacity, differentiation ability, haematopoiesis support, immunomodulation function, and increased inflammatory alterations within the BM through some intracellular pathways such as Notch and Wnt and extracellular modulators secreted by MSCs abnormally, including increased expressions of inflammatory factors and decreased expressions of hematopoietic factors, contributing to the development and progression of MDS. Therefore, MSCs can be targeted for the treatment of MDS and leukaemia. However, it remains unclear what drives MSCs to behave abnormally. In this review, dysregulations in MSCs and their contributions to myeloid haematological malignancies will be discussed.