The book "Differences in Grammatical Uses between Spanish and Portuguese" offers a comprehensive analysis of the grammatical differences between Spanish and Portuguese. It is particularly aimed at Brazilian learners who encounter specific challenges while learning the Spanish language. In 22 chapters, the essential aspects of the Spanish language are addressed, always making a comparison with Portuguese. This approach allows learners to better understand the differences and similarities between both languages and to overcome the typical difficulties that arise from their proximity. The book serves as supplementary material to more extensive grammar works and is designed to support and facilitate the learning process.