I'm removing old wallpaper. The wall underneath is uneven. What to do?

Hi Wendy, If you have drywall, here's a video how to! https://www.youtube.com/watch?v=8caJy9jImhc

Good luck!

skim coat it with pre-mixed joint compound.... https://www.youtube.com/results?search_query=how+to+skim+coat+walls+after+removing+wallpaper

Bead board, if your style is not too modern. I have it half way up in some od my rooms and it looks great.

If your home is an older home (pre-1950's), if might be lathe and plaster. If the plaster isn't crumbling and cracking off the walls, it can be leveled. For the best results, hire someone who is experienced at applying plaster and can even out the hills and valleys you have on your walls now. (Lots of homes with plaster walls were DIY by original homeowners. The degree of hills and valleys is evidence of their skills at applying the plaster. Especially the mail order kit homes sold by Sears and other companies. Not everyone hired skilled labor to assemble and finish these kit homes. When plastering, they began in the private rooms such as bedrooms and kitchens to develop the skills before committing to the public rooms such as living rooms and parlors).

If the walls are deteriorating and falling apart under the wallpaper it is best to remove the old plaster and start over. Either use fresh plaster or replace with drywall. (Depends if you are "fixing" or "restoring" , And your budget).

Drywall that has bowed over the years could be evidence of past or current water leakage or structural issues. If you have ruled that out and know it's not a current problem, the walls can be leveled with a skin coat of drywall compound. More severe repairs can be fixed with 1/4 inch thick drywall applied over entire existing wall surface with shims behind the worst spots to bring the walls to an even and level appearance.