Food security is an important challenge facing humanity. Crop failure, food shortages and food-price spikes have occurred in recent years and can be expected to continue under a changing climate. These events signify the need for timely information on crop condition and reliable forecasting. Earth observations and crop models can be used to provide timely and accurate information on crop area distribution, crop condition and yield forecasts from local to global scales. Such information can help farmers in management decisions and at the broad scale mitigate food supply crises and stabilize markets. Earth observations play a central role in crop monitoring activities. Recent advances in sensor technology (e.g. micro satellites, SAR, passive microwave, fluorescence); satellite-based crop models; big data analytics and high performance computing, open opportunities to develop new and improved methods and techniques for within-season crop monitoring, and yield forecasting. NASA Harvest is a new, multidisciplinary program commissioned by NASA and led by the University of Maryland to advance the use of satellite observations in decision-making related to the food security and agriculture, domestically and globally. The Agricultural Modelling Intercomparison and Improvement Project (AgMIP) is an international program advancing the development and use of crop models. The assimilation of Earth Observations in Crop Models is an important area of research. This session is organized for remote sensing researchers and crop modelers to share and discuss recent developments in the field of crop monitoring and modeling. The first part of the session will provide an overview of crop monitoring and modelling with an emphasis on Earth Observations. The second part of the session will focus on recent research on crop mapping, crop growth and condition monitoring and yield forecasting and will be followed by an open discussion on research needs and challenges.