This paper provides a comprehensive review of the present state of second language reading research and computer-assisted glossing for reading comprehension and vocabulary acquisition. Although computer-assisted language learning, in general, and computer-assisted glossing, in particular, are often cited as facilitative pedagogical and self-study tools for second language reading development (Chun, 2001; Al-Seghayer, 2003; Ko, 2005; Blake, 2007; Stockwell, 2011), the state of computer-assisted glossing research presents a much less compelling and far more nuanced picture of efficacy and facilitation (Ariew & Ercetin, 2004; Bowles, 2004; Taylor, 2006, 2009; AbuSeileek, 2008; Sato & Sazuki, 2010). Research on glossing for reading comprehension presents a mixed collection of findings suggesting facilitation (Leffa, 1992; Lomicka, 1998; Ko, 2005) and inhibition (Hegelheimer, 1997; Plass et al., 2003; Akbulut, 2005; Sakar & Ercetin, 2005), although affective and attentional benefits of glossing for reading comprehension are widely acknowledged. On the other hand, research on incidental vocabulary acquisition as a result of glossing – and particularly multimedia glossing – suggests significant effect and a compelling rationale for ulitization of glossing tools in classroom and self-study contexts (Ariew & Ercetin, 2004; AbuSeileek, 2008; Taylor, 2009; Stockwell, 2011; Aljabri, 2011).