Summary: Different styrene‐ and acrylate‐based organic‐inorganic polymer composites incorporating magnesium hydroxide were successfully synthesized using MPTMS as a coupling agent and MgCl2 as an inorganic precursor. The polymer composites were prepared by free‐radical emulsion polymerization following different procedures. The samples were investigated by means of FT‐IR spectroscopy, XRD, TGA, DSC, and rheometry. It is shown that the preparation method does only affect the ratio of organic to inorganic component, but not the chemical structure of the composites. The obtained polymer composites consist of Mg(OH)2 particles which are linked covalently via MPTMS groups to the polymer backbone.