Self-determination refers to skills used to experience a quality of life consistent with one's preferences, strengths, and needs. Theoretical and empirical literature has identified contextual opportunities for children to learn and use these skills in their everyday activities and routines. The present study used an investigator-developed observational coding system to describe and quantify preschool teachers' use of teaching practices that could promote young children's foundational self-determination skills. Twenty-one preschool teachers who had children with and without identified disabilities or developmental delays enrolled in their classrooms were observed for 15 min during two types of preschool classroom activities: child-initiated and teacher-directed. Teachers' use of practices ranged from 6 to 60 occurrences across five self-determination skill categories, with an average of 24.43 occurrences in 30 min. Self-regard, self-direction, and self-advocacy practices were more frequently used than self-regulation and social problem-solving practices. Exploratory analyses of the observational data suggested differences in teachers' use of self-determination teaching practices across the two types of activities and positive correlations between teachers' use of self-determination teaching practices and the observed quality of teacher-child interactions. Implications of the study findings for teaching practices teachers can use to promote young children's self-determination skills during classroom activities are discussed in the context of inclusive and high-quality early childhood education.