"He's just on top of his game," Cubs manager Joe Maddon said. "He knows where his fastball is going, and that's why he's been so good."
• Past winners
Lester opened the week by tossing eight scoreless innings against the Phillies in a 6-4 Cubs win on June 6. He scattered four hits and struck out nine while walking none.
He closed the week Sunday by allowing one unearned run in seven innings in a 13-2 win over the Braves. He allowed five hits, struck out seven and once again didn't issue a walk.
This is Lester's third career weekly award and first in the NL.
Cash Kruth is a reporter for MLB.com. Follow him on Twitter at @cashkruth. This story was not subject to the approval of Major League Baseball or its clubs.