The purpose of this paper is to analyze systematically the issues and approaches of existing research on language and ideology. In order to accomplish this purpose, this paper first defines ideology as ‘the ideas, beliefs, and values and the material process of (re)producing them that contribute to promoting and legitimizing the sectoral interests of certain social group or power’, noting that such ideology causes social problems when it serves primarily the sectoral interests of a mainstream group or ruling power, often working in a false and deceptive form through distortion and dissimulation of objective reality. Then, this paper raises the necessity to divide the research into two types: the research on ideology ‘about’ language and the research on ideology ‘through’ language. Finally, based on the theoretical discussion above, this paper explores the sociolinguistic research tasks and prospects of research on language and ideology by analyzing the representative research cases and approaches related to Korean language and its usage. This paper particularly focuses on monolingualism and standard language ideology in the case and approach of the research on ideology ‘about’ language, and sexism and gender ideology in the case and approach of the research on ideology ‘through’ language.