Can I extend my stay in Thailand on a Non-Immigrant B Visa after attending business meetings?

They have to set a term, otherwise people come and go for 1 year business meetings.

Depends on what kind of work she is going to do if she need a work permit of not, but according her visa she can stay the rest of the Admitted to Stay period.

I get immigration and labor are different offices. It's just when you apply at the embassy, if you're planning on a biz trip longer than 15 days they want u to apply for work permit. Editing this: seems it's not a requirement for all embassy websites. It was for the Washington DC one but not London.

So if Peggy only works for 12 days no work permit needed, she can stay the the rest of the 90days as a tourist and it's ok?

If you organize or attend meetings; give opinions, lecture, or present in a meeting; participate in training sessions, tour, seminar, art or cultural exhibitions, sports competition, or any other activities as prescribed by the Cabinet;, you do not need a Work Permit from the Ministry of Labor. If you want to work inside Thailand you need a Work Permit from Minsitry of Labor. To get into Thailand you need for both options the Non Immigrant B visa which gives you 90 days of stay. Staying inside Thailand is arranged by the Royal Thai Immigration Bureau and working in Thailand by the Ministry of Labor, two different offices with different guidelines.

I've seen this on the embassy website too. If u have a business trip longer than 15 days then you need to apply for a work permit. The requirements are exactly the same as the work permit to work. The embassy websites are a bit confusing Bc non b is for working and for business trips in Thailand. I wish they would call it something else. Maybe non c. Anyhow im curious about the answer for this too.

a Work Permit is required to work in Thailand and has nothing to do with your permitted to stay in Thailand. Two total different things from different offices.