By TMZ

Former heavyweight champion Mike Tyson and his wife are suing financial advisors they claim embezzled more than $300,000 from them ... and ultimately cost them around $5 million.

Tyson filed the suit against SFX Financial Advisory Management Enterprises today in L.A. -- and in the docs, obtained by TMZ, he claims SFX advisor Brian Ourand siphoned off the money from his accounts.

Additionally, the Tysons claim Ourand purposely gave them "deceptive and faulty financial advice."

According to the suit, Ourand has quite the pedigree -- having represented several other superstar athletes like Allen Iverson, Dikembe Mutombo, and Juwan Howard.

Tyson, and his attorney Mark Geragos, claim Ourand's scheme, which they discovered in 2011, has stopped Tyson from digging out of the bankruptcy he filed 10 years ago -- and set him back $5 mil.

For example, in the lawsuit, Tyson claims the embezzlement forced him to mortgage his house to pay bankruptcy lawyers -- and he also had to borrow money to pay the IRS.

In the docs, Tyson says SFX admitted Ourand embezzled the $300k ... returned a portion of the funds -- and then tried to get the Tysons to sign a settlement.

The Tysons turned down that offer ... and are now suing SFX and Ourand for the $5 mil.

Ourand no longer works for SFX, and according to the docs he's living comfortably in Miami and working for another financial advisory firm.

We've called Ourand for comment, but no word back yet.

Tags: Mike Tyson