The 2020 Census language program was successfully executed and became the most robust language program ever built for the decennial census. For the 2020 Census, we provided an opportunity for people to respond in 12 non-English languages (online and phone) and offered video and print guides in 59 non-English languages. Final translations reached millions of households across the nation, providing them with critical information about the census. The creation of these complex, interrelated products required thorough planning and the engagement of multiple teams of experts and professional translation staff. The purpose of this handbook is to share detailed information about our best practices and to provide guidance for organizations planning similar translation projects.