The girls were taken by Boko Haram, an Islamic extremist group in the country, and the Nigerian government does not know where they are even though more than two weeks have passed.
The kidnapping was "abominable, criminal, an act of terrorism and really merits the fullest response possible first and foremost from the government of Nigeria," Clinton said in an interview with ABC's Robin Roberts Wednesday.
She had previously posted a message on her Twitter account, reading, "Access to education is a basic right & an unconscionable reason to target innocent girls. We must stand up to terrorism." It is a reference Boko Haram's objections to women receiving education.
Clinton added at the event that the Nigerian government has been "somewhat derelict in its responsibility" to protect children in the country, and need to "make it a priority."
President Obama has called the kidnapping "awful" and sent in a team of U.S. military, law enforcement and other experts to help the Nigerian government. The team includes hostage negotiators and intelligence experts.
The kidnapping has sparked worldwide outrage and launched a social media campaign using the hash tag, #BringBackOurGirls. First lady Michelle Obama posted a picture of herself on Twitter holding a sign with those words written on it.
During the interview, Clinton was also asked about the renewed congressional investigation into the 2012 attacks on the U.S. diplomatic facility in Benghazi and whether she was "satisfied with the answers" she had received in other assessments of how the attack happened.
"Absolutely," Clinton replied. "Of course there are a lot of reasons why, despite all of the hearings, all of the information that's been provided, some choose not to be satisfied and choose to continue to move forward. That's their choice and I do not believe there is any reason for it to continue in this way, but they get to call the shots in the Congress."