Oprah Move Over, Beyonce ... My Lemonade is Fabulooouuus!

Oprah didn't get filthy rich by ignoring golden opportunities ... which could explain why she's riding Beyonce's lemonade bandwagon straight to the bank.

O recently made a move to expand merchandising rights of her personal "Oprah's" brand to include bottled water, energy drinks, coconut water ... and lemonade.

Always the savvy entrepreneur, Oprah filed the docs -- obtained by TMZ -- a few weeks after Bey's "Lemonade" album became a smash hit.

No word on when the beverages will roll out ... but Oprah's neighbors in Montecito better prepare for the most expensive lemonade stand of all time.