<p>Rare earth (RE) elements as “Industrial vitamins” play a key role in modulating the mechanical properties of advanced aluminum (Al) alloys. However, only few Al-RE intermetallics, such as L1₂ Al₃Sc and Al₃Er are appreciated. In this work, BCC, FCC, and HCP Al-RE (RE = Sc, Y, La–Lu) ordered structures are screened by their phase stability and transformation tendency using first-principles calculations combined with cluster expansion. The formation energies indicate the existence of common stoichiometric ratios (3:1, 2:1, 1:1, 1:2, 1:3) Al-RE ordered phases on the convex hull, which transit from a close-packed (FCC/HCP) to BCC, and finally to FCC/HCP ordered structures with respect to RE concentration. Those close-packed (FCC/HCP) and BCC ordered phases exist various phase transition pathways, such as martensitic and ω phase transformations. The predicted Al-RE phase transition behaviors are consistent with available experimental observations and thus provides a viable way to tune the mechanical properties of advanced Al alloys in a broader RE range.</p> Graphical Abstract <p></p>