Abstract: Underpinning planetary science is a deep history of observation and, more recently, robotic exploration within the Solar System, from which models of planetary processes have been constructed. Concurrently, thousands of planets have been discovered outside our Solar System that exhibit enormous diversity, and their large numbers provide a statistical opportunity to place our Solar System within the broader context of planetary structure, atmospheres, architectures, formation, and evolution. Indeed, the field of exoplanetary science has rapidly forged onward toward a goal of atmospheric characterization, inferring surface conditions and interiors, and assessing the potential for habitability. However, the interpretation of exoplanet data requires the development and validation of exoplanet models that depend on in situ data that, in the foreseeable future, are only obtainable from our Solar System. Thus, planetary and exoplanetary science greatly benefit from a symbiotic relationship with a two way flow of information. In this talk I will briefly describe the critical lessons and outstanding questions from planetary science, the study of which are essential for addressing fundamental aspects for a variety of exoplanetary topics. I will particularly focus on the gaps in our knowledge regarding Venus within the context of modeling planetary habitability. I will discuss various factors that relate to a possible habitable past of Venus, including orbital evolution. I will outline exoplanet target selection for testing the conditions of runaway greenhouse and present examples of potential Venus analogs. Finally, I will discuss how many of these planetary science issues may be translated into exoplanet observables that will yield critical insight into current and future exoplanet discoveries.