A portative organ (portatif organ, portativ organ, or simply portative, portatif, or portativ) (from the Latin verb portare, "to carry") is a small pipe organ that consists of one rank of flue pipes and played while strapped to the performer at a right angle. The performer manipulates the bellows with one hand and fingers the keys with the other. The portative organ lacks a reservoir to retain a supply of wind, thus it will only produce sound while the bellows are being operated. The instrument was commonly used in secular music from the twelfth to the sixteenth centuries.
The portative is constructed simply in order to make it as portable as possible. The pipes are arranged on a small rectangular windchest and supplied with wind by one or two bellows placed at the back, in front or at the right side of the instrument. The row of pipes is supported by posts at either end and an oblique bar. The simplest style of keyboard on the portative consists of one slider for each pipe. When a slider is pushed in, the corresponding pipe sounds. The slider is restored to its normal position by a horn spring. Some instruments use the reverse of this action, with keys featuring knobs or handles.
The portative is a smaller instrument than the positive organ, which features more ranks of pipes and a larger keyboard. The portative also should not be confused with the regal, a small keyboard instrument that contains a rank of short-length reed pipes instead of flue pipes.
Towards the middle of the thirteenth century, miniatures of illuminated manuscripts depict portatives with modern, balanced-action keyboards. An example can be seen in the Spanish manuscript known as the Cantigas de Santa Maria,, which contains fifty-one miniatures of instrumentalists. It is evident from the position of the organist's thumb in these miniatures that the keys are pressed down to make the notes sound. There are nine pipes and nine keys, which is sufficient for a C-major diatonic scale of one octave with an added B-flat.
One of the most well-known modern proponents of the portative organ is Dolly Collins, who accompanied her vocalist sister Shirley on many albums of traditional English folk songs.