Ritchie now has five goals in six games since returning from injury and his strikes secured Bournemouth's first back-to-back wins in the Championship since 1990.
The lively winger rounded off good work from Ryan Fraser to smash past an inspired Marek Stech after 50 minutes to open the scoring.
Former Swindon star Ritchie then saw his curling effort on 57 minutes take a wicked deflection off the unlucky Shane Duffy to double the lead.
Eunan O'Kane got in on the act after 64 minutes to deliver the knock-out blow and secure the points, shooting left footed past Stech for his first of the season.
It was the Cherries' first win at home since early October having lost three out of their last four at the Goldsands Stadium.
Eddie Howe's men started full of confidence though and Stech had to make a flying save after seven minutes to keep out an Andrew Surman header with his fingertips.
Yeovil were looking to catch their opponents on the break, with in-form Ishmael Miller causing the most danger.
The Nottingham Forest loanee came close to giving his side the lead after 12 minutes, hitting the post from a tight angle after taking on O'Kane with a powerful run.
In an end to end contest it was turning into a busy day for Stech, with the Czech goalie keeping out a Ritchie header superbly after 16 minutes.
Bournemouth's top scorer Lewis Grabban had a golden chance to get his 10th of the season three minutes later but was thwarted by Stech once again after being put through one on one by the magnificent Ritchie.
The home side were throwing the kitchen sink at their south-coast rivals but Charlie Daniels, Elliott Ward and Grabban were unable to find a way past the solid Stech towards the end of the half.
When Ward thought he had scored in first-half injury-time, referee Craig Pawson ruled it out for a push in the penalty box.
The game was over 20 minutes after the break thanks to the quick-fire treble.
Shell-shocked Glovers boss Gary Johnson made a triple substitution in a bid to turn it around but to no avail, with his team left firmly in the relegation zone.
The home side were rampant and Surman should have added a fourth on 68 minutes but launched his effort over the bar when well positioned inside the box.
Bournemouth clearly fancied boosting their goal difference and relentlessly pushed forward, with Ritchie inches away from a hat-trick with 10 minutes remaining.
Moments later Yeovil's leading scorer Ed Upson almost pulled a consolation back but his shot cannoned back off the upright with Lee Camp beaten.