Macronaria is a clade of sauropod dinosaurs from the Middle Jurassic (Bathonian) to Late Cretaceous Periods of what are now North America, South America, Europe, Asia, Africa and Australia. The name means 'large nostrils' (from scientists' reinterpretation of Greek makros, 'long,' as 'big,' and Latin nares, 'nostrils'), in reference to the large nasal openings high on the head that probably supported fleshy resonating chambers. Macronaria consists of a single main group, Titanosauriformes, along with several more basal taxa. Titanosauriformes in turn contains the brachiosaurids and the titanosaurians and is one of the largest sauropod groups, which also contains some of the longest, tallest and most massive dinosaurs of all time.

Macronaria is a clade of sauropod dinosaurs from the Middle Jurassic (Bathonian) to Late Cretaceous Periods of what are now North America, South America, Europe, Asia, Africa and Australia. The name means 'large nostrils' (from scientists' reinterpretation of Greek makros, 'long,' as 'big,' and Latin nares, 'nostrils'), in reference to the large nasal openings high on the head that probably supported fleshy resonating chambers. Macronaria consists of a single main group, Titanosauriformes, along with several more basal taxa. Titanosauriformes in turn contains the brachiosaurids and the titanosaurians and is one of the largest sauropod groups, which also contains some of the longest, tallest and most massive dinosaurs of all time.