Creating effective online learning courseware requires instructional and pedagogical approaches (Quinton, 2009), but also working knowledge in visual design and aesthetics (Hashimoto & Clayton, 2009). Research has demonstrated that aesthetics plays a significant role in shaping user responses to products and websites (Lavie & Tractinsky, 2004; Lindgaard, 2007). Users also draw on aesthetic factors to judge usability and credibility (Malamed, 2015). From the usability and accessibility perspective, visual design can be considered an essential component of the online learning experience. For example, students with colour impairment will not be able to distinguish between red and green colours (Reyna et al., 2016). In online learning, it is, therefore important for educational institutions and faculty to consider the educational function of visual content and the aesthetic judgments that are being made by students (Reyna, 2013). The rules that govern aesthetics are supported by different disciplines such as visual design (Kimball, 2013), neuroscience (LeDoux, 1989, 1992), psychology (Chang et al., 2002), and multimedia learning principles (Mayer, 2008). Including visual content and applying aesthetic standards during online course development can ultimately improve not only the visual appearance of course content but can also improve how students react to and interact with those courses (Reyna, 2013). The aim of this paper is to discuss the importance of visual design enablers for online learning such as layout design, colour theory, typography, and use of images. The link between the enablers and multimedia learning principles is examined. The implications of visual design on usability, accessibility and online learning are discussed.