The tree grows up to 10 metres (33 feet) tall. It has deciduous, pinnate leaves 10–20 centimetres (4–8 inches) long. The plants are dioecious, with separate male and female trees. The flowers are apetalous and unisexual and borne in panicles.^[4]

The fruit is a drupe, containing an elongated seed, which is the edible portion. The seed, commonly thought of as a nut, is a culinary nut, not a botanical nut. The fruit has a hard, cream-colored exterior shell. The seed has a mauve-colored skin and light green flesh, with a distinctive flavor. When the fruit ripens, the shell changes from green to an autumnal yellow/red and abruptly splits partly open. This is known as dehiscence and happens with an audible pop. Humans selected the trait of splitting open.^[5] Commercial cultivars vary in how consistently they split open.

Each mature pistachio tree averages around 50 kilograms (110 pounds) of seeds, or around 50,000 seeds, every two years.^[6]