Maize (Zea mays L.) is the most grown cereal crop in the world (839 million tons in 2012). According to its agro-economical importance, maize has received tremendous attention from research communities of academic, state, and industry origin. In this manuscript, we aspire to provide readers with the first comprehensive review of proteomics studies performed on maize within a 1987–2012 time period. The following topics are presented here: maize proteome profiling, developmental proteomics, response to abiotic and biotic stress, maize phosphoproteomics, tissue-specific wild-type versus mutant analyses, heterosis, seed viability, maize allergens, and safety assessment of genetically modified maize. Tissues, organelles, subcellular compartments, secretomes, methods, phenomena, and pertinent proteins were summarized and referenced in tables and figures to provide readers with expediently accessible information in the context of up-to-date achievements. This review illustrates maize proteomics as a firmly established research area with laboratories around the world diligently advancing our knowledge of diverse aspects of maize biology.