Walker (centre) receives the congratulations of his team-mates
Willie Walker's last-minute drop goal earned Worcester their first league win in over three months and denied Wasps their first league win at Sixways.
Two Danny Cipriani penalties put Wasps on top on as they dominated early on.
Centre Alex Grove's try put Worcester ahead before Cipriani added his third goal, but Wasps wasted chances through Mark van Gisbergen and Josh Lewsey.
The teams traded penalties until Pat Sanderson drove Worcester forward in one last attack, and Walker struck.
Worcester coach Mike Ruddock on centre Alex Grove:
"His man-of-the-match award was thoroughly deserved. He made breaks, he tackled really well and his tackle early on against Josh Lewsey really lifted our team.
"We thought if a youngster could do that to an international we all had to get behind that effort and tackle that way.
"It was a critical moment for us and people really followed suit from there on. He got a try and it was a dream debut for another youngster from our academy coming through and doing well."
Wasps assistant coach Leon Holden on coaches Ian McGeechan and Shaun Edwards being stranded in France: "If they could have got here it would have been a nice bonus. Everything was explored and everything was tried.
"If we had won no-one would have been asking why they were not here. We have had situations before with coaches not being here. Our preparation was the best it has been all season so we can't use that as an excuse.
"In the first half we played some great rugby but failed to capitalise on some of the opportunities we created."
Worcester: Gear; Garvey, Luscombe, Grove, Benjamin; Walker, M Powell, Mullan, Lutui, Tuamoepeau, Rawlinson, Bowley, T. Wood, Sanderson, Horstmann.
Replacements: R Powell for M Powell (52), Morris for Mullan (52), Fortey for Lutui (65), Talei for Tuamoepeau (68), Kitchener for Bowley (11).
Not Used: Carlisle, Fellows.
Wasps: Van Gisbergen; Mitchell, Waldouck, Lewsey, Voyce; Cipriani, Reddan; Holford, Ward, French, Shaw, Skivington, Birkett, Betsen, Hart.
Replacements: Robinson for Reddan (76), Barnard for Holford (40), Webber for Ward (55), Veale for Shaw (48), Ellis for Hart (52).
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