No. As of this writing, the mod's CurseForge page lists exactly one loader, Forge, for both of its game versions (1.20.1 and 1.19.2). There is no Fabric file in the listing, and we have not found a Fabric build released by Pixel_Coder.
That matters because Forge and Fabric mods are not interchangeable. Each loader has its own API, and a mod built against one will not load on the other.
Why the mod is Forge-only
The project is tagged on CurseForge as made with MCreator, a tool that generates mod code from a visual editor. MCreator can target several loaders, but a creator still has to choose, build and maintain each one. Pixel_Coder has chosen Forge. We will not guess at the reasons or promise a Fabric port, because nothing public points to one.
What Fabric players can do
Run a separate Forge profile
This is the practical answer. You do not have to abandon your Fabric setup; the Minecraft Launcher and the CurseForge app both let you keep multiple profiles side by side. Create a Forge 1.20.1 profile just for horror sessions, add GeckoLib and the mod, and keep your Fabric profile untouched. The install guide covers both the app and manual methods.
Rebuild your pack on Forge
If you want The One Who Watches inside a larger pack, check whether your other mods also offer Forge builds for 1.20.1. Many popular ones do. Swap them in one at a time and test, rather than moving everything at once.
Compatibility layers
Tools exist that try to load mods from one loader on another. Results vary widely, the mod author does not support them, and problems you hit are hard to report. We do not recommend them for a mod whose atmosphere depends on its animations and sounds working correctly.
Watch out for "Fabric version" downloads
Because people search for it, some sites post files labelled as a Fabric port. Unless the release comes from the author's own project page, treat it as unofficial. The mod is published under an All Rights Reserved licence on CurseForge, so reuploads and repackaged versions are not authorised by default. More on that in our download safety guide.
In short
Forge only, for now. Keep a dedicated Forge profile and you can play it without touching your Fabric setup. Check the compatibility table on the home page for the full picture.

How to install The One Who Watches mod on Forge
Does The One Who Watches work on Minecraft 1.21 or 1.21.11?
The One Who Watches on Bedrock and MCPE: what's real