The reality star/entrepreneur revealed the loss Monday morning, saying ... "Today, my heart breaks as I say goodbye to my precious chihuahua, Harajuku Bitch.💔🐶"

Harajuku got a pretty complete eulogy, as Paris added, "For an incredible 23 years, she filled my life with so much love, loyalty, and unforgettable moments.🥰 She lived a long, beautiful and iconic life, surrounded by love until her final peaceful slumber."

Paris says HB was "more than just a pet; she was family to me, a loyal friend who was always by my side through every twist and turn life brought my way."

She ended her post by thanking HB for blessing her life with unconditional love -- "You will forever be my little angel, forever missed, and forever loved. 😇 You may be physically gone, but the imprint of your pawprints on my life will never fade.🐾"

It's been a tough year for Paris as a dog mama.

You'll recall, her dog Diamond Baby went missing last year ... and still has not been found, despite PH offering a "big reward" for her return.