Nine terracotta bricks and brick fragments, containing incised drawings of different types of buildings, were discovered at the large Muara Jambi temple complex in eastern Sumatra. Likely dating from between the second half of the ninth and the first half of the fourteenth centuries, these bricks contain the oldest graphic representations of Sumatran architecture. While two of these designs have been previously published, the brick images have not been thoroughly analyzed in order to determine what new light they shed on the domestic architecture and building traditions of early lowland Sumatran settlements. To address this lacuna, we analyze the bricks and their archaeological context in order to interpret when the images were made, who created the images, the purpose behind them, the types of architecture depicted on the bricks, and the reasons behind the diversity of building types represented. Having argued that the majority of bricks shows domestic architecture reflecting a variety of cultural influences, we conclude by suggesting that the presence of such images supports the scholarly view that Muara Jambi was a multiethnic trading community.