Dyche, 21, joined Guiseley at the start of the season and spent last season on loan at Boston and Ashton United.
Farsley manager, Adam Lakeland, said: "Jack is a player I have liked for quite sometime, so I'm delighted he has joined us.
"Jack is young, versatile, has great pace and is a goalscorer. He offers us a number of options as he can operate in wide areas, play as a striker, and also at full back, which gives us additional competition for places which is always good.
"I look forward to working with Jack and he goes straight into the squad for Saturday's game against Brighouse Town. I'd like to thank Guiseley Manager Marcus Bignot for allowing Jack to play in the FA Trophy, which you aren't always able to do with dual registration signings."
The Leeds-born forward was previously with Scunthorpe before being released in the summer and has made six appearances in National League North this season.
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