This list is by no means complete but if you are looking for some advice on some dishes to try while traveling in Thailand, this should get you started.

While many dishes are prepared similarly all over the country, each region of Thailand has a local cuisine that is indigenous to that area. Bangkok has a style. The “Northern” region around Chiang Mai has a style. And the Northeastern part of the country, which is also known as “Isan” has a distinctive style that overlaps with nearby areas of Lao. In reviewing the list below we find that many of our suggestions are from Isan.

Likewise you can probably also find be a version of many of these dishes in any country in Southeast Asia that you might visit.

• Kanom Krok is a sweet little coconut and corn custard treat available in street food markets that is best eaten warm.
• Mak Bea or Banana Blossom Salad is usually served warm. Mak Bea is the Thai name but In Lao it is known as tam hua plee.  You’ll find a version of Banana Blossom Salad in every country in Southeast Asia.
• Gaeng Som Soup is a seafood and vegetable “sour” (meaning with lime juice) curry soup. It may also be spelled as Kaeng som.  Some restaurants will serve Gaeng Som as a non-soup stir fry dish but we love the soup.  The two best versions we ever had were both in restaurants near the city of Surin in Northeast Thailand (Isan).
• Gai Yang is Isan style charcoal grilled chicken. You’ll find Gai Yang everywhere from hole-in-the-wall dirt floor places to fine dining establishments all over Isan and in Lao as well.  But if you are in Bangkok, the restaurant Likit Gaiyang, near the Rajadamnern Boxing Stadium is a good place to try it. You may also find it spelled as Kai Yaang.
• Som Tam is Green Papaya Salad (with chili and lime); a Thai staple side dish. Som Tam can be very (hot) spicy and depending on where you order it, can feature a healthy dose of fish sauce.  In Lao, Green Papaya Salad is known as Tham Mak Hoong.
• Panang Gai, Chicken in green or yellow curry with coconut milk; typically topped with crushed peanuts is served in many Thai restaurants in the west but what you’ll eat in Thailand will be a revelation.  
• Pak Bung is our favorite green vegetable dish ins SE-Asia.  It is stir-fried leaves from the water Morning Glory plant with garlic, It is known by some as “water spinach”. You’ll find this in Lao also.
• Sai Krok Isan is fermented “sour” pork sausage originating in Isan. There is a very similar dish in Lao known as Luang Prabang Sausage.
• Miang Kana is an assemble your own appetizer with a variety of ingredients wrapped in a green leaf.  What is served will vary by the restaurant but typically you’ll find little piles of dried shrimp, fried pork skin, peanuts, Thai chili, chopped onion, galangal, lime & tamarind sauce served with green leaves for wrapping.  Miang Kana is seen on many menus but if in Bangkok; Krua Apsorn is a great place to try it.  Some other things to try at Krau Apsorn: crab omelet, gaeng luang lai bua (lotus stem yellow curry with shrimp), grilled giant river prawns, (if available) stuffed chicken wings, Coconut I-scream (dairy free coconut sorbet) and another desert of a black bean dish that shared a similar taste and texture as black eyed peas in tapioca pudding.
• Is it the best in the world? Well we haven’t eaten Pad Thai in every restaurant in the world but Pad Thai Thip Sami has a huge following and many including us recognize it as among the best in Bangkok.  Thip Sami is also known locally as Pad Thai Pra Du Pee, which translates as “Pad Thai restaurant near the Ghost Gate”.  For about $2.50 – $3.00 you’ll get a great plate of food and beverage.  Our favorite drink is the frozen coconut water.  There’s often a line to get in but it moves quickly and the service is friendly.
• You’ll see Mango with sticky rice in lots of places all over Thailand but a good one in Bangkok is a street vendor near Pad Thai Thip Sami.
• Larb or Laab is minced meat with vegetables and lime juice. It can be made with any meat including water buffalo.  This is another Isan dish you’ll see all over Lao as well.
• Take a mixture of squiggly soft egg noodles, crispy deep fried wheat noodles, a rich fragrant curry-based broth, sides of crunchy pickled greens, sliced shallots and lime juice and you have kôw soy (also known as khao soi), a dish that has become virtually synonymous with the northern Thai city of Chiang Mai.  The lunch section of the Chiang Mai restaurant Huen Phen is a great place to try this one.  Khao Soi is usually served only for breakfast or lunch.