Hosackia pinnata, synonym Lotus pinnatus, is a species of legume native to western North America from British Columbia to California.

Its distribution extends into British Columbia in just a few rare occurrences near Nanaimo.

It grows in moist to wet habitat, such as bogs and spring meadows.

It is a hairless perennial herb lined with leaves each made up of green oval leaflets each 1 to 2.5 centimeters in length.

The fruit is a slender, elongated legume pod up to 5 centimeters long but just a few millimeters wide.