Leigh Day and Co., a law firm representing Libyan military chief Abdul Hakim Belhadj, claims Straw was complicit in the rendition of the Libyan commander.
"The civil action is against Mr. Straw personally and seeks his response to allegations that he was complicit in torture and misfeasance in public office," the firm said in a statement.
In December, Belhadj, Libya's military commander who worked with NATO forces during Operation Unified Protector, claimed London played a role in his illegal rendition and torture while he was held in Libya's Abu Salim jail.
He was captured in Thailand in 2006 and transferred to the Libyan prison. There, he says, he was tortured by Western and Libyan personnel because he was accused of supporting al-Qaida.
The law firm said it had documents and diaries suggesting Straw played a role in the rendition. It said the former foreign secretary could face criminal prosecution as the London Metropolitan Police broaden an inquiry into the allegations.
British lawmakers are investigating the country's alleged involvement in so-called extraordinary renditions. A judge in Washington ruled that it was permissible for U.S. intelligence agencies to withhold documents from London, however.
Ben Emmerson, U.N. special rapporteur on human rights and counter-terrorism, rapped the U.S. decision as "promoting impunity for state officials of the U.K. who may have been party to grave human rights violations."