Three new species of Justicia (Acanthaceae), J. montealegrensis, J. multiglandulosa, and J. paraensis from the Brazilian Amazon, discovered during the preparation of a taxonomic treatment of genus for the state of Pará, are herein described and illustrated. Their geographic distribution, habitat, preliminary conservation status, taxonomic comments, line drawings, photo plates, and comparison of diagnostic morphological characters with those of similar taxa are also provided.