A considerable amount of research has been done to connect or integrate separate numerical models. The Environmental Modeling Research Laboratory (EMRL) has developed a generic file format, the eXtensible Model Data Format (XMDF). One of the objectives of the XMDF project is to facilitate the spatial interpolation and data-sharing necessary when linking models. The objective of this research is to investigate how model linking capabilities can be added to the XMDF by defining a Model Linkage Object (MLO) that is compatible with current model linking frameworks. A potential design for an MLO is defined in this thesis after a detailed review of existing model linking frameworks. The major model-linking systems studied in this research are FRAMES, DIAS, and OpenMI. Other software was also researched and a brief description of each is provided. To limit the scope of this research the MLO is analyzed for a two-dimensional mesh using only two of the model linking systems. FRAMES was chosen because the Army Corps of Engineers has already done extensive work with this software. OpenMI was selected because of its ability to link models during runtime.