<![CDATA[Mathematical ideas embedded in local cultural artifacts offer opportunities to connect abstract school mathematics with cultural practices. This study explored ethnomathematical concepts in the motifs of Siak woven shawls produced by Tenun Siak Annisa. A qualitative exploratory approach was employed at the Tenun Siak Annisa craft site in Sungai Mempura, Siak, Riau, in July 2023. Data were collected through observation, semi-structured interviews with a craftsperson, and documentation, and examined using domain, taxonomic, componential, and cultural-theme analyses with methodological triangulation. The findings identified four principal motif domains—pucuk rebung, tampuk manggis, siku awan, and siku tunggal—containing concepts related to plane geometry, geometric reflection, and arithmetic series. The geometric figures included equilateral triangles, rhombi, and hexagons. Reflection was evident in mirrored motif arrangements, while regular sequences of motif elements were interpreted in terms of arithmetic-series concepts. These findings indicate that Siak woven-shawl motifs have potential as contextual cultural resources for mathematics learning while also supporting the documentation of local cultural knowledge. The study contributes empirical documentation of connections between Siak weaving motifs and mathematical concepts, providing a foundation for developing culturally contextualized mathematics learning materials.]]>
