The effect of rabbit-assisted interventions on the anxiety levels of first-grade children at a primary school was analyzed. At the beginning of our research, no rabbit-assisted intervention was applied for 6 weeks in order to establish the level of stress caused by the start of the education period. We then alternated 6-week-long periods with and without rabbit-assisted intervention. The level of anxiety in children was assessed every three weeks both in the assisted and non-assisted periods, using the State–Trait Anxiety Inventory for Children, STAI-C. One of the examined classes did not apply the integrating policy while the other class contained pupils with special education needs (called the integrating class). Rabbit-assisted interventions proved to be efficient, as anxiety level scores were significantly lower during the animal-assisted periods. The rabbits actively initiated encounters with humans, not only in the framework of animal-assisted interventions, but also at other occasions. In cases of discomfort, the rabbit retreated to the cage and stayed inside for a short time. The children displayed signs of pleasure when the rabbits approached them. The favorable effect of animal assistance was more apparent in the integrating class. It could be concluded that rabbit-assisted interventions were suitable for decreasing the anxiety levels of elementary school children, improving the efficacy of the educational ability of teachers.