Phosphorylation is the most studied posttranslational modification involved in signal transduction in stress responses, development, and growth. In the recent years large-scale phosphoproteomic studies were carried out using various model plants and several growth and stress conditions. Here we present an overview of online resources for plant phosphoproteomic databases: PhosPhAt as a resource for Arabidopsis phosphoproteins, P3DB as a resource expanding to crop plants, and Medicago PhosphoProtein Database as a resource for the model plant Medicago trunculata.