The company did not comment on whether consumers would notice any difference after the removal of the ingredient, which can be used to make food shiny or more brightly coloured.
Mars and other firms have disputed claims of health risks associated with consumption of titanium dioxide, a white pigment that is used in bakery products, sweets, cosmetics and other products such as paint.
It is allowed in many countries, including the US, UK, Canada and New Zealand.
In the US, a high-profile 2023 effort in California to ban the ingredient was defeated, but efforts in other states continue to bubble.
The White House's Make America Healthy Again report published earlier this month also spotlighted titanium dioxide and other food additives as a key concern.
Mars, which also makes M&Ms, Snickers and Kind snack bars, did not explain why it had made the decision, which was first reported by Bloomberg.
The company did not respond when asked whether the change would apply to Skittles sold outside the US.
"Our commitment to quality is what has enabled Mars to be enjoyed by consumers for over a century, and nothing is more important than the safety of our products," a spokesperson said in a statement.
"All our products are safe to enjoy and meet the high standards and applicable regulations set by food safety authorities around the world, and that's something we will never compromise on."