Pakistan currently have 111 points, one ahead of India, while Australia and England have 108 points each.
Pakistan achieved the No. 1 Test ranking for the first time since the current rankings system was introduced in 2003 after it drew the series against England 2-2.
Pakistan's cause was also helped by Sri Lanka, who defeated Australia 3-0, while a wet ground in Port of Spain denied India the opportunity to defend the top spot as they won their four-Test series against the West Indies 2-0.
Pakistan currently have 111 points, one ahead of India, while Australia and England have 108 points each.
The top seven Test sides are separated by just 16 points.
The Mohammad brothers: Pakistan cricket's first family
PHOTOS: Pakistan thrash England at Lord's; lead series 1-0
2nd Test: England overpower Pakistan to win by 330 runs, level series
Third Test: England destroy Pakistan to take series lead
4th Test: Pakistan crush England by 10 wickets to level series