Many food products contain a network of fat crystals. The size and shape of these triglyceride crystals is extremely important in producing the good physical properties and texture for a high-quality final product. Control of crystal habit can affect a fat’s structure and hence the resultant behaviour. In this work the effects of phospholipids on the crystal habit of triglyceride crystals have been investigated. Optical and scanning electron microscopy, DSC and X-ray diffraction have been used. The effects of certain phospholipids on the crystallisation of fats have been shown, and large changes to crystal habit have been demonstrated. These changes are caused by the interactions of the phospholipid molecules with the crystallising triglyceride molecules. Interference with the crystallising molecules causes changes to the shape and size (habit) of the resultant fat crystals. Effects on nucleation and crystal growth are demonstrated. These dramatic changes to the crystal habit can have a significant effect on the properties of the resultant fat system. For example the process of fat fractionation could be significantly enhanced. Alternatively, the network structure of fatty products could be controlled or altered opening up the possibility of the development of new and improved products