Over the past five years, investment screening has gained in prominence as a policy tool. The COVID-19 pandemic has once more accelerated this trend. Investment screening is a justified policy instrument to protect national security and public order. However, an overly broad interpretation of these interests, an increasing number of covered sectors, and opaque decision-making could create new investment barriers and distort worldwide investment flows. This policy brief aims to provide an overview of screening mechanisms in G20 countries, the criteria that trigger the screening process, the covered sectors, and designated thresholds. This is to help provide a basis for the G20 to deal with investment screening by establishing comparisons and best practices.