She will need a visa for sure.....depending on your nationality, she may be able to get one upon arrival at the airport..Use the Maha service at the airport for arrivial..they can assist in the visa upon arrival at the airport..

Here is an copy from an online search:
Tourist Visa
Citizens of the following countries, who hold a valid passport, are issued visitor entry visas before arriving at the border. However, the holders of this visa are not allowed to work in Qatar with or without payment. Visas are usually issued in 2 days and remain valid for 14 days, which could be extended by another 14 days.

The countries covered under this visa include The United States, Britain, France, Italy, Germany, Canada, Australia, New Zealand, Japan, the Netherlands, Belgium, Luxembourg, Switzerland, Austria, Sweden, Norway, Denmark, Portugal, Ireland, Greece , Finland, Spain, Monaco, the Vatican, Iceland, Andorra, San Marino, Lichtenstein, Brunei, Singapore, Malaysia, Hong Kong, South Korea.