Emergency Support for STEM Act This bill provides FY2021 appropriations for grants to states and, through them, subgrants to eligible public elementary and secondary schools and nonprofit programs to support hands-on learning opportunities in science, technology, engineering, and mathematics (STEM) education, including through remote learning, after-school activities, and innovative learning opportunities (e.g., robotics competitions). The amounts provided by the bill are designated as an emergency requirement pursuant to the Statutory Pay-As-You-Go Act of 2010 (PAYGO) and the Senate PAYGO rule.