Old Gala House started life as a tower house in the 15th century, but was extended over the centuries and is now a museum, art gallery and offices.

The original tower was built by the Pringle, or Hoppringill, family in 1457, after they had been granted the lands of Gala by the Earl of Douglas. It originally stood to the west of the Old Town of Gala.

In 1583 the original tower was either replaced by, or more likely incorporated into, a larger building by Andrew Pringle. A carved stone panel from the new tower, now installed in the gate lodge, depicts Andrew Pringle and his wife Mariota Borthwick, daughter of John, the 5th Lord Borthwick, holding heraldic shield carrying their initials.

Consisting of two storeys and an attic, with an entrance at first floor level, it is aligned approximately north-west to south-east. It has variously been described as a bastle house or pele tower.

In 1611 Sir James Pringle, the last Pringle Laird of Gala, built a new self-contained wing, extending to the south-west from the south-western corner of the 16th century castle to form an L-shape.

The new 7 bay wing was three storeys in height, the southern two thirds of the ground floor forming a large hall, with a single smaller chamber at the northern end. On the rear of the wing, to the west, is a projecting external square stair tower.

Small windows can be seen on the outer wall of the ground floor of the new wing.

Sir James Pringle moved to the family seat of Smailholm Tower in 1635, when his daughter Jean Pringle married Hugh Scott, and Old Gala House became a Scott property. A painted timber ceiling, rediscovered in 1952, was created the same year to commemorate the marriage, and the house remodelled further.

At some point in the 18th century a new wing was added to the south end of the 17th century block, extending to the west to form a U shape.

Around 1830 gabled corner bays were added either side of the 1611 block, and further work was carried out on the interiors in 1860. During the course of this work a fireplace lintel, previously plastered over, was uncovered. Measuring some 2.9m wide by 0.5m tall, it is carved with Latin inscriptions and the arms and initials of Sir James Pringle and his wife Jean Ker of Linton.

Old Gala House remained home to the Scotts until 1872, when another Hugh Scott commissioned David Bryce to build New Gala House. However New Gala House was demolished in 1985.

Ownership of Old Gala House passed to Scottish Borders Council, and in 1988 it was converted by Page and Park Architects, reopening as a museum. It now also contains an art gallery, office space and a conference centre.