Lady Gaga is walking the walk when it comes to helping California's wildfire victims ... and she's doing it with arms full of pizza.

Gaga hit up a Red Cross Shelter in the L.A. area Tuesday night to deliver goodies -- food, coffee and other items -- to hundreds of people displaced by the Woolsey fire. No tip necessary. She's all good.

Can't say she's not a woman of her word. Remember, Gaga -- who was also forced to evacuate -- went to a shelter over the weekend and told evacuees she'd stand by them through the crisis.

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Kinda perfect timing that Tuesday happened to be World Kindness Day, and Gaga encouraged others to follow in her footsteps.