Andrew Flintoff, who captained England in their two most recent Test series against Sri Lanka and India, will resume the Test captaincy once he has recovered from an ankle injury.
South Africa-born Strauss, a former Middlesex captain, led the side during the recent One-day series against Sri Lanka, losing all five games.
Chairman of selectors David Graveney said selectors hoped to have a clearer picture of the state of Flintoff's ankle injury this week.
"Andrew Flintoff will have his ankle re-assessed in the next few days and we will have a clearer idea then of when he will be able to return to the team and take over the captaincy," he said.
"We are fortunate to have a very capable deputy available in Andrew Strauss and he will continue to lead the Test side in Andrew Flintoffs absence."
Strauss said he was excited about leading England against Pakistan although it would be on a temporary basis.
"It will be a great honour to captain England in a Test Match for the first time and to lead the team out at Lords will be a special moment for me," he said.
"At this stage, I have been asked to take on the captaincy on a temporary basis until Andrew Flintoff is available for selection again."
Flintoff has said he is pleased with the progress of the injury but believes being fit in time for Pakistan on July 13 would be "a big ask".
After the disappointing Sri Lanka series - which ended 1-1 - Strauss last week made clear he was keen to become a full-time successor to the injured Michael Vaughan.
Following a fourth knee operation on Monday, Vaughan has been ruled out for the rest of the English season and is doubtful for the Ashes series in Australia later this year.
Strauss said he respected the selectors' decision and would be happy to step back when Flintoff returned.
"He proved to be an inspirational captain in the Test Series in India and everyone in the dressing room is hoping that he can make a speedy return to the side," he said.