This thesis examines the social psychological processes and factors involved in willingness to participate in collective action among older people. This work is framed within two social psychological theories, i.e. Identity Process Theory (Break well, 1986) and Social Representations Theory (Moscovici, 1984). The research used the construct of barriers to collective action. The barriers were conceptualised at different levels of analysis and were considered to embody both identity and representational aspects. The research comprised three studies. Study 1 used a questionnaire among 277 older people in order to establish the extent to which older people participate in different types of collective action. Two types of participation were identified, i.e. 'active' and 'passive'. Disability in specific areas and non-participation in a group were related to lower involvement in collective action. Study 2 was designed to explore the social issues older people are concerned about, to identify the types of collective action they are likely to take, and to examine perceived barriers to engaging in collective action. Thirteen focus groups were run (n= 59) and the data was content analysed. Findings showed that older people perceive a need for social change for a wide variety of social issues and the importance of several aspects of identity and belief systems as either facilitators or barriers to engaging in collective action was revealed. Collective action was defined in terms of type of action (from individual to group action) and type of goal (from collective expression to collective change). Different social psychological factors accounting for willingness to engage in collective action were identified. These were investigated in the following study. Study 3 (n= 345) investigated the relationships between certain social psychological factors and collective action. Differences in perceptions of barriers according to five levels (intraindividual, interpersonal, intragroup, intergroup, societal) were shown. These were related to the way they give meaning to older people's identity structure and social beliefs. A model of collective action was tested. Willingness to participate in collective action was directly predicted by political trust, previous experience of collective action, perceived effectiveness of collective action and perceived barriers. Identity and ideology factors acted indirectly through previous experience, perceived effectiveness and perceived barriers. This work has implications for future research on the study of processes involved in explaining the generation of collective action and for the study of the socio-cognitive processes affecting ageing.