Does the Pope decide who becomes a saint?

The process by which someone becomes a saint is called canonization. The Catholic church has canonized around 3,000 people -- the exact number is unknown because not all saints were officially canonized. According to the church, the pope does not make someone a saint -- the designation of sainthood only recognizes what God has already done. For centuries, saints were chosen through public opinion. In the 10th century, Pope John XV developed an official canonization process.

So overall No.

Clarification:

Investigations into a candidate's qualifications to be declared a saint are carried out under the auspices of the Sacred Congregation for the Causes of Saints. Once they feel they have sufficient information, they pass the case along to the pope who makes the final decision.