make light invisible but still illuminates

[wr_uk]

Is there a way to have a light illuminate but make the actual light invisible?

[yolov]

If you mean that you want the light to be invisible for the camera - there's an 'invisible' checkbox option for each light in V-Ray.
Then if you mean that you want it to not cast shadows or be invisible in reflections, refractions and so on - there's other options - either use trace sets (for reflection/refraction visibility - that's done with the vrayObjectProperties node) or do shadow linking or disable shadow casting for the light and so on.
What's the particular result you want to achieve?