This article examines the relationship between Finnish teachers' participation in professional training on teaching the school language as an additional language and culturally responsive education, and the implementation of linguistically and culturally responsive classroom practices. The study further explores how these practices vary across different teaching positions, including class teachers, subject teachers, and special education teachers. Additionally, the article assesses the impact of teachers' background factors—such as prior experience with linguistically and culturally diverse students (LCDS) and the proportion of LCDS in their schools—on the relationship between training and classroom practices. The primary aim of this article is to evaluate whether professional training enables teachers to effectively address increasing classroom diversity, and to identify strategies for enhancing teacher preparation to better support LCDS. The study used survey data from 820 schoolteachers, with the sample size ranging from 557 to 567 teachers across Finnish municipalities. Logistic regression with average marginal effects was employed to estimate the likelihood of teachers adopting linguistically and culturally responsive teaching practices. The findings show a positive relationship between training and the implementation of these practices, with an even stronger effect among teachers who received training in both school language as an additional language and culturally responsive education. The adoption of such practices also varied according to the teachers' position, with different positions influencing the likelihood of employing these methods. This study highlights the importance of comprehensive teacher training programs that are tailored to the specific roles and responsibilities of educators, regardless of their experience or the number of LCDS they teach.