Green Discovery (www.greendiscoverylaos.com) offer a range of tours, taking in every site and activity you could want to see in every part of the country. They have offices all over the country so trips can be booked locally or all in one go from Vientiane. They specialize in adventure activities but they also provide a full range of tours covering towns and villages, and historical sites.
For Remote Asia (www.remoteasia.com), the flagship activity is motorcycling, with other tours as well. The Laos Heritage and Cultural Expedition is an 11-day experience, taking in all the major sites of interest from Luang Prabang in the north to Wat Phou in the south. They also offer tours tailored to your needs and these can be put together beforehand.
Diethelm Travel (www.diethelmtravel.com) is a Pan-Asian operator offering a whole range of tours both long and short all around the country.
Exotissimo (www.exotissimo.com) is another Pan-Asian tour company offering a range of escorted tours throughout the country.
Inter Lao Tourism (www.interlao.com) was one of the first operators on the scene and has been established in Laos since 1989. It has Lao ownership and all staff is Lao and has very detailed local knowledge.
Note: This information was accurate when it was published, but can change without notice. Please be sure to confirm all rates and details directly with the companies in question before planning your trip.