The main aim of this paper is to make an explanatory proposal regarding social phobia incorporating a process including a vulnerability phase, another regarding its genesis, and a third referred to the relevant variables participating in the maintenance of the disorder. The model postulates the existence of an association among a negative social context and a group of particular variables of the individual that facilitate the genesis of the disorder either in a direct or an insidious way. In the negative social context three main groups of variables are distinguished: family, school, and other contexts. Among the characteristic variables of the individual we identify evolutionary and not evolutionary aspects, escape responses, personality variables and learning deficits. The association is supposed to be established from the processes of classic and instrumental conditioning, modeling and instruction. The model attributes a key role to the uncertainty perceived by the subject and to the escape and avoidant responses considering the onset, development and maintenance of the disorder. Finally, some implications of the model are presented regarding the subtypes included in the DSM-IV-TR (APA, 2000) as well as treatment.