Cambodia Democracy Act of 2018 This bill directs the President to apply property-blocking and visa restriction sanctions against each senior official of the Cambodian government, military, or security forces who has directly and substantially undermined democracy in Cambodia and committed or directed serious human rights violations. Sanctions may be suspended for up to one year if the President certifies to Congress that Cambodia is making progress toward ending government efforts to undermine democracy, ending human rights violations, and conducting elections that allow for the participation of credible opposition candidates.