The action comes following allegations concerning his conduct in a national newspaper.
Agbonlahor, 29, had been out of the immediate first-team picture having been placed on a fitness programme by caretaker manager Eric Black.
A statement read: "Aston Villa Football Club have today suspended Gabby Agbonlahor pending an internal investigation.
"This is following allegations concerning his conduct at the weekend.
"There will be no further comment from the club in relation to this matter until the investigation has been completed."
This latest Agbonlahor incident, which allegedly took place as Villa were relegated from the Barclays Premier League last weekend, comes just weeks after an investigation into his behaviour during a break in Dubai.
No action was taken over that matter but Black later decided the player's condition was not of the required level and ordered him to follow a personal fitness regime for two weeks.
The matter also brings more fresh turmoil on Villa following their relegation and the shock resignation of two board members on Monday
On the field, the team have lost their last nine games and have been without a manager since parting company with Remi Garde last month.
Amid this ongoing sense of chaos, supporters will continue their protests against owner Randy Lerner during this Saturday's game against Southampton at Villa Park
The Aston Villa Protest Group are urging fans to carry on with the 'Banners out on 74' campaign in which messages such as 'Proud History - What Future?' have been held up for Lerner's attention.
A statement from the group read: "We are going down without even a whimper, we are a rotting from the top down and the fans are suffering desperately.
"This Saturday vs Southampton we are continuing Banners Out on 74
We are imploring all supporters to stand firm with us
Now more than ever it is vital that we are persistent in asking the right questions of our risible owner."
Villa were not willing to comment on the group's statement when contacted by Press Association Sport.
Uncertainty over the club's immediate direction has now increased following the departures of directors David Bernstein and Mervyn King
The pair had only taken up their boardroom positions in 2016 and both were key figures in the search for a new manager.
Former Leicester boss Nigel Pearson remains the favourite for the position despite the club's difficulties
David Moyes, Simon Grayson and Steve Bruce are among those also to have been linked.
Agbonlahor's future at the club is now also unclear
The striker has had spells out of favour this season and scored just one goal during the campaign, against Norwich in February.
Source : PA
Source: PA