Selena Gomez is selling her Calabasas mansion after owning it for just 1 1/2 years ... a mansion that had its share of drama.

Gomez purchased the 7,700 square foot estate for $3.7 million ... and just days after moving, a stalker showed up. He showed up again a few days later and was arrested. After that, Selena called 911 on 3 separate occasions, fearing an intruder.

It's the second home Selena bought that was targeted by stalkers. It's surprising her current home is not tucked away in a gated community. It's a safe bet her next purchase will be in a more secure location.

It does make sense to sell now ... Selena will be on tour for most of 2016.

She's listed the house for $4.5 million.