Spelt flour (or Triticum Spelta as it is known scientifically), contains gluten as it is part of the wheat family. The gluten however is slightly different from what is typically seen in wheat or wheat-related ingredients.
The gluten found in most wheat, rye, barley, etc., has different properties than what is seen in spelt. The gluten found in the aforementioned is more described as chewy or like glue versus the type found in spelt. That is typically described as brittle and soluble.
Spelt, from a nutritional point of view, is closely related to wheat. There are some nutrients like Omega 3, & 6 that it has an edge on. Even though spelt contains gluten, it has been said to be easier to digest for people that may have trouble with gluten. That does not mean if you have Celiac disease or an actual gluten allergy (not just sensitivity) this is a safe alternative.
If you are looking to substitute a gluten free ingredient to spelt, then you could try some of the following; brown rice flour, buckwheat flour, chia flour, etc. With a little bit of research you will find many more.