The 34-year-old midfielder has made over 180 appearances for the Saddlers since arriving from Leyton Orient in July 2011.
“I’m delighted that Adam has agreed to extend his stay with us,” manager Dean Smith told the club’s official website.
“It was never in any doubt. The only reason it has taken so long is that our holidays meant that we kept missing each other.
“Adam and I go back a long way. The type of player and person he is fits perfectly into the way we try to do things here.
“He’s fully committed to the cause and leads by example. He has a phenomenal work ethic, something which the other lads can only learn from.
“He has been a big influence here in recent seasons and I’m pleased that this will continue into the new campaign.”