ACTA may refer to:
- Anti-Counterfeiting Trade Agreement, an intellectual property trade agreement
- Administrative Council for Terminal Attachments, a standards organization for terminal equipment such as registered jacks
- Alameda Corridor Transportation Authority, in southern California
- American Council of Trustees and Alumni, an education organization
- Atlantic County Transportation Authority, a transportation agency in Atlantic County, New Jersey
- Australian Community Television Alliance, an industry association representing community television licensees in Australia
Acta may refer to:
- Acta (software), early outliner software
- Actin assembly-inducing protein (ActA Protein), a protein used by the bacteria Listeria monocytogenes to propel itself through a host cell
- A term used in the title of historical, ecclesiastic, or academic publications, such as:
- Acta Arithmetica, a number theory publication
- Acta Crystallographica, a family of scientific journals about crystallography
- Acta Diurna, daily Roman official notices
- Acta Sanctorum, hagiographical accounts of saints
- Acta Senatus, minutes of the discussions and decisions of the Roman Senate
- Acta Universitatis Sapientiae, a series of scientific journals edited by the Sapientia University
- Manny Acta, manager of the Cleveland Indians in Major League Baseball