Acacia stenophylla, commonly referred to as the shoestring acacia, is an evergreen tree in the family Fabaceae and native to Australia. It is not considered rare or endangered.

Acacia stenophylla varies in characteristic and size from a rounded, multi-stemmed shrub to a spreading tree. A. stenophylla grows from 4–20 m (13–66 ft) tall, often stemming into branches at the trunk from about 1 m (3.3 ft). Bark is dark-grey to blackish and rough, branchlets are smooth to sericeous and sometimes angular.

The phyllodes are strap-like, 15–40 cm (5.9–15.7 in) long, 2–10 mm (0.08–0.4 in) wide, straight to slightly curved, slightly rough, free from hair or very finely puberulous, acute to acuminate, apex is often strongly curved. Veins are copious and closely parallel.

The racemes are 3– to 5-headed, with stems 2–15 mm (0.08–0.6 in) long, which are slightly rough or with appressed minute hairs. The peduncles are 6–13 mm (0.2–0.5 in) long. The flower heads are creamy-white to pale yellow in colour, spherical and 6–9 mm (0.2–0.4 in) in diameter. Flowers are pentamerous, with sepals three-quarters united.

The pods are moniliform, up to 26 cm (10 in) long, 8–12 mm (0.3–0.5 in) wide, woody-leathery textured, smooth except micro-puberulous between seeds. The seeds are longitudinal, elliptic, 7–9 mm (0.3–0.4 in) long, dark brown, lacking an aril, funicle enlarged, are folded at the seed apex. Flowering time is often irregular, although mainly occurring in autumn.

A. stenophylla is highly salt tolerant and moderately frost and drought tolerant. The average minimum annual rainfall that the tree needs is around 400 mm (16 in) per year.

Acacia stenophylla normally flowers from March to August, although it can flower irregularly throughout the year. Seed pods turn woody as they mature from October to December and produce approximately 6–12 viable seeds/g.

A. stenophylla seeds germinate prolifically. After major floods, seedlings can often be present along the flood-line, but only a very small proportion of these persist.