Are there buses that travel from Guadalajar,Mex. to Tapachula,Mex?

I can't find a bus company that goes from Guadalajara to Tapachula,Mexico.

The Bus company that has always been most predominant in SOUTHERN Mexico is Cristobal Colon which has first class service (maybe not quite as 1st class as you might find in the North but still pretty nice) all over Tabasco, Oaxaca and Chiapas states. Tapachula is a very hot and humid city and I try to avoid it if I am going to Guatemala (it is on the border). Traveling through from Guadalajara to Tapachula you would almost have to go through Mexico City. I think you still have to change bus stations there to the Southern Mexico City Bus Terminal to head out for the South. Although I agree with the previous poster about the beauty and fun of Oaxaca City (although there is trouble there from time to time with protests etc.), I prefer San Cristobal de las Casas (the 'Swiss' village of Mexico) and Comitan, Chiapas and then on in to Huehuetenango in Guatemala. San Cristobal is amazing and Highly popular among European tourists. Comitan is an old Spanish colonial city very much worth seeing! I dream of retiring there. Enjoy your trip!

There might not be one that goes directly between those cities, but you could certainly take one to Mexico City, and then from there to Tapachula. Or there might be a different route if you wanted it. Every decent-sized Mexican town has first-class bus service to it.

If you want to break up such a long trip, there are several nice towns along the way. Oaxaca City is very nice.