If my parents live overseas and are US citizens/residents have a social security number and I support them economically, can I claim them as dependents in my taxes?

Please see the eligibility requirements to claim your parents as dependents.

Qualifying relative

• They don't have to be related to you (despite the name).
• They aren't claimed as a dependent by someone else.
• They are a U.S. citizen, resident alien, national, or a Canadian or Mexican resident.
• They aren’t filing a joint return with their spouse.
• They lived with you the entire year.- If the person is related to you they do not need to live with you.
  
• They made less than $4,150 in 2018.
• You provided more than half of their financial support. More info

Please see Pub 501 for more information on the above requirements: https://www.irs.gov/pub/irs-pdf/p501.pdf