Significant advances have been achieved in generating soil moisture (SM) products from satellite remotesensing and/or land surface modeling with reasonably good accuracy in recent years. However, the discrepancies among the different SM data products can be considerably large, which hampers their usagein various applications. The bias of one SM product from another is well recognized in the literature. Biasestimation and spatial correction methods have been documented for assimilating satellite SM productinto land surface and hydrologic models. Nevertheless, understanding the characteristics of each of theseSM data products is required for many applications where the most accurate data products are desir-able. This study inter-compares five SM data products from three different sources with each other, andevaluates them against in situ SM measurements over 14-year period from 2000 to 2013. Specifically,three microwave (MW) satellite based data sets provided by ESA’s Climate Change Initiative (CCI) (CCI-merged, -active and -passive products), one thermal infrared (TIR) satellite based product (ALEXI), andthe Noah land surface model (LSM) simulations. The in-situ SM measurements are collected from theNorth American Soil Moisture Database (NASMD), which involves more than 600 ground sites from avariety of networks. They are used to evaluate the accuracies of these five SM data products. In general,each of the five SM products is capable of capturing the dry/wet patterns over the study period. However,the absolute SM values among the five products vary significantly. SM simulations from Noah LSM aremore stable relative to the satellite-based products. All TIR and MW satellite based products are rela-tively noisier than the Noah LSM simulations. Even though MW satellite based SM retrievals have beenpredominantly used in the past years, SM retrievals of the ALEXI model based on TIR satellite observa-tions demonstrate skills equivalent to all the MW satellite retrievals and even slightly better over certainregions. Compared to the individual active and passive MW products, the merged CCI product exhibitshigher anomaly correlation with both Noah LSM simulations and in-situ SM measurements