E-textiles design integrates materials not usually native to textile design e.g. conductive yarns and optical fibers. E-textiles themselves are soft systems; a computational composite made up of fluid and rigid materials, each component essential to the functionality of the e-textile. The making process represents another complex system. The process of integrating electronics and textiles requires that the designer negotiates and unifies the properties of tools, materials, and manual and machine enabled processes. E-textile designers leverage the affordances of unconventional materials to enable new functional and aesthetic potential while working within the constraints of different aspects of the e-textiles system; the tools, materials, and the requirements of electronics. This paper presents a discussion on affordance in e-textile design, drawing from literature detailing e-textile design processes and the author’s practice. Affordance offers a new perspective in understanding the relationship between aspects of the e-textile design process. This paper focuses on the affordances of textile tools whilst also considering new affordances provided by e-textiles materials, and affordances and constraints in material manipulation. In the analysis of textiles tools, four key affordances that impact on e-textiles design were identified: design complexity, manual intervention, automation and tactile feedback. These exist to a greater or lesser degree, depending on the tool. Manual intervention, tactile feedback and design complexity are particularly beneficial for novel e-textile design, while automation can be problematic in e-textiles development since it can prevent the designer from enacting new techniques. Although the beneficial affordances are seldomly found together, there are examples of textiles tools that possess these affordances. Nevertheless, there remains a need for more tools that possess these affordances to allow for novel e-textiles development in the future.