Aspiration of coda /s/ has been widely studied throughout the Spanish-speaking world, although within the Madrid dialect there have only been two studies quantifying /s/ realization (Momcilovic, 2005; Turnham & Lafford, 1995). In the first, Turnham and Lafford (1995) examine the extralinguistic factors that condition /s/ realization, considering the nonstandard variants of velarized and elided /s/ in their analysis. In contrast, Momcilovic (2005) does not include the velarized /s/ as a specific category in her study, but rather quantifies rates of aspirated, elided and assimilated /s/. In this way, the actual variants present and their distribution within the Spanish of Madrid has not been clearly established. The velarized /s/, of particular interest in this dissertation, is distinct from most cases of /s/ weakening because it does not fit into the typological weaking paradigm of [s] > [h] > [ø], and furthermore may not be a case of lenition at all (Henriksen & Harper, 2016). Given the curious /s/ variant present in the Madrid dialect, the current investigation sought to learn more of the social meaning and perception of the velarized /s/, utilizing the matched guise language attitudes technique to do so. It is found that the velarized /s/ is a marker of Madrileño identity, and that it is mainly associated with negative connotations, most strongly observed among the Madrileño participants. This dissertation contributes the first language attitudes study conducted on /s/ in Madrid, revealing both the social meaning attached to velarized /s/ and the importance of the speakers’ social characteristics in their perception of this variant. Secondly, a production study was conducted in order to offer a clearer picture of the coda /s/ variants present in the Madrid dialect and their respective distribution. The significant factors found to condition /s/ realization include syllabic position, reading time, reading order and the number of Madrileño grandparents a speaker has. Most importantly here, it is seen that the aspirated variant actually appears more frequently than the velarized /s/. Together these studies contribute a greater understanding of velarized /s/, filling a lacuna in what was previously known of coda /s/ in the Madrid dialect.Spanish and Portugues