This dissertation explores the interaction of the term structure of interest rates and the macroeconomy for the United States and United Kingdom. In particular, using a dynamic factor yield curve model, the three essays of this dissertation investigate the macroeconomic sources of parameter instability in the US and UK term structure. First, this dissertation explores if parameter instability in the term structures is reflected in structural breaks in latent yield curve factors - level, slope, and curvature. I test for a single and for multiple structural breaks. The results indicate that parameter instability in the US term structure is adequately captured by the structural breaks in the level and slope factors. Similarly, there is evidence that structural breaks in the level and curvature factors characterize parameter instability in the UK term structure. Next, I assume the dynamics of the US term structure follow a two-state Markov process. This allows interest rate dynamics to switch between the two states as frequently as the data dictates. A switching model is proposed which gives macroeconomic insight into an asymmetric monetary policy effect during expansions and recessions. A second proposed switching model provides evidence of a great moderation in the US term structure where there is a dramatic decrease in the volatility of yields. Lastly, I investigate the interaction of the UK term structure and macroeconomy. In order to establish a definitive one-to-one correspondence between macroeconomic fundamentals and latent yield curve factors, I estimate a dynamic yield curve model augmented with macroeconomic variables. Through impulse response analysis, I find that during the inflation-targeting period for the UK, the curvature factor is directly related to real economic activity. I then use this established interaction between the term structure and macroeconomy to gain macroeconomic insight into regime changes in the UK term structure. Using Markov-switching dynamic yield curve models, I estimate the term structure and find that periods of low volatility correspond to regimes where real economic activity and monetary policy have a greater effect on the bond market. Periods of high volatility are driven by inflation expectations having a greater influence on bond pricing.