Tarlac State University (TSU) is a multi-ethnic and multicultural institution with a student population that is predominated by the Kapampangan, Ilocano, and Tagalog ethnolinguistic groups. This paper is a comparative study of ethnic and national stereotypes and self-stereotypes of these three ethnolinguistic groups. Using a modified Katz and Braly trait checklist, as well as their uniformity index, this paper was able to: 1) compare and contrast the uniformity as well as positivity of the three ethnic stereotypes; 2) compare and contrast the uniformity as well as positivity of the three ethnic stereotypes with their corresponding ethnic self-stereotypes; 3) determine the national self-stereotypes of the three ethnolinguistic groups; and 4) compare and contrast the uniformity as well as positivity of the three national self-stereotypes with their corresponding ethnic self-stereotypes. This paper is significant in understanding the peaceful and productive co-existence of the said three ethnolinguistic groups not only in TSU but also in Tarlac City, and Tarlac Province. This paper is also significant in exploring how multi-ethnicity and multicultural condition may contribute towards imagining national identity and building the nation.