A senior State Department official told CNN Thursday Tillerson wasn't planning on attending because he had other business at the State Department to attend to, but declined to elaborate.
Tillerson did not have any specific meeting listed in his public schedule at the time of the speech. His public schedule just said he was spending the day holding meetings and briefings at the State Department.
Despite his notable absence, the State Department would not officially confirm he was not in attendance, referring all questions to the White House.
CNN has reached out to the White House for comment.
The former CEO of ExxonMobil had advised the President not to abandon the accord, which sets voluntary carbon emissions reduction targets.
On Friday, in his first public remarks since the announcement, Tillerson shrugged off the significance of Trump's decision, emphasizing the United States' "terrific record" on reducing greenhouse gas emissions, and saying he hopes people can "keep (the decision) in perspective."
"Well, it was a policy decision," Tillerson told reporters at the State Department. "And I think it's important that everyone recognize the United States has a terrific record on reducing our own greenhouse gas emissions."
"I don't think we're going to change our ongoing efforts to reduce those emissions in the future," he added. "So hopefully, people can keep it in perspective."
In his confirmation hearing in January, Tillerson said he thought it was "important that the United States maintain its seat at the table" on the issue of climate change, adding, "No one country is going to solve this alone."
US allies have publicly criticized the Trump administration's decision to leave the deal, which was signed by the Obama administration and took effect in November.
Only two other countries had previously rejected the accord: Nicaragua -- which felt the deal did not go far enough in cutting emissions -- and Syria.
Tillerson heads to Australia and New Zealand this weekend, where the President's decision is sure to be raised by his foreign counterparts.
Australia's Prime Minister told reporters earlier on Friday that Trump's decision to leave the Paris agreement -- and earlier decision to abandon the Trans-Pacific Partnership trade agreement -- has led some to "herald a US withdrawal from global leadership," though he added that "we should take care not to rush to interpret an intent to engage on different terms as one not to engage at all."
CORRECTION: This story has been updated to reflect that Tillerson did not attend the speech.