The study examines Colombian teachers' acculturation expectations towards students of Venezuelan, Ecuadorian, Indigenous, and Afro-Colombian origin, and the role of psychosocial factors in shaping these expectations. Three hundred and fifty-three practicing teachers (73% women), with a mean age of 37.6 years, participated in the study. This cross-sectional correlational-predictive study used an online questionnaire with validated scales measuring pro-diversity beliefs, intercultural sensitivity, optimal contact, negative stereotypes, and acculturation expectations. Data were analysed using descriptive statistics, ANOVAs, bivariate correlations, and multiple linear regressions. The results showed high scores for pro-diversity, intercultural sensitivity, and preservation; moderate scores for optimal contact; and low scores for negative stereotypes, assimilation, and separation, with no sex differences. Expectations of preservation were higher toward Indigenous and Afro-Colombian groups, while expectations of assimilation and separation were higher toward Venezuelans and Ecuadorians. Pro-diversity beliefs, intercultural sensitivity, and optimal contact predicted higher expectations of preservation, whereas negative stereotypes predicted greater assimilation and separation. In conclusion, teachers' expectations vary by the target acculturating group and combine appreciation of diversity with assimilationist biases toward immigrant students, highlighting conditional inclusion and the need to strengthen teachers' intercultural education and training.