The present investigation was aimed at the evaluation of possible interactions between mirtazapine and selected solid lipids that are commonly used to develop solid lipid nanoparticles (SLNs) and nanostructured lipidic carriers (NLCs). The solids lipids explored were palmitic acid, stearic acid, glycerylmonostearate, cutina CPPH, sterotex NF, gelucire 50/13, hydrogenated castor oil and compritol 888 ATO. The techniques used were Differential Scanning Calorimetry (DSC), Fourier Transform Infrared Spectroscopy (FTIR), Hot Stage Microscopy (HSM) and Isothermal Stress Testing (IST) studies. In some cases, the DSC results indicated the possibility of drug-solid lipid interactions which was further ruled out by performing HSM studies. Moreover, IST studies were also used to further confirm the compatibility between the drug and selected solid lipids. And the findings from these studies indicated compatibility between mirtazapine and solid lipids that can further be used to develop SLNs or NLCs.