||Lee, Jong Kun. (2021). Nominative case markers, ellipsis of case markers, focus, and topic in Korean. The Linguistic Association of Korea Journal, 29(4), 21-43. The purpose of this paper is to investigate how various morphemes are used to indicate topics in Korean. While in many cases, the so-called nominative case marker i/-ka occurs to indicate focus in Korean, this study claims that these so-called nominative case markers can be also used as a special form of topic markers in Korean and offers various data to support this claim. In addition, this paper discusses how bare nominal phrases can occur to indicate topics in place of nominal phrases marked with the topic marker un/-nun. This study further argues that, in principle, to indicate topics in Korean, the topic marker un/-nun occurs when there is a contextually relevant alternative comparable with the topic while the so-called nominative marker i/-ka occurs when there is no relevant alternative in terms of the situation-internal point of view. This paper also gives evidence that, contrary to the claims made by Lambrecht and Michaelis (1998) and Oh (2009), nominative case-marked noun phrases in Korean can indicate ratified as well as unratified topics.