Ethnic minorities, such as Latinx people of Hispanic or Latino origin, and women earn fewer engineering degrees than Caucasians and men. With shifting population dynamics and high demands for a technically qualified workforce, it is important to achieve broad participation in the engineering workforce by all ethnicities and both genders. Previous research has examined the knowledge of and interest in engineering among students in grades five and higher. In contrast, the present study examined elementary school students in grades K-5. The study found that older students in grades 4 and 5 had both greater knowledge of engineering occupational activities and greater interest in engineering than younger students in grades K-3. Moreover, Caucasian students had greater knowledge and interest levels than Latinx students. There were no significant differences between boys and girls, nor any significant interactions among gender, grade level, and ethnicity. A significant positive correlation between knowledge of engineering occupational activities and interest in engineering was also found. The findings suggest that early engineering outreach interventions are important. Such early interventions could potentially contribute to preserving the equivalent interest levels of males and females for engineering as students grow older. Also, ethnic disparities in engineering knowledge and interest could potentially be mitigated through early interventions.