Haylie Duff -- I'm Selling My L.A. Pad ... Just Like My Sister

Haylie Duff -- best known as Hilary Duff's older sis -- is trying to unload her Toluca Lake crib for $1.8 million ... just months after her sister sold a home in the same area.

Haylie bought the 4,064 square-foot-pad 4 years ago -- right around the time she was filming a couple of made-for-TV movies -- for a cool $1.75 million.

After several years in a less-than-stellar real estate market -- the Duffster listed it this week for a mere $50k more than she paid. Which leaves her a very tiny profit margin.

The 5-bedroom, 6-bath house is pretty cool ... boasting New England style decor ... hardwood floors ...a marble kitchen ... cathedral ceiling ... pool and spa. Not to mention, it sits inside a gated community.

Back in August, Hilary sold her 5,260 square foot Toluca Lake home for $6.25 million.