How do I vertically center the text in an Excel label's caption?

There's no way to do it directly. This post has a clever way to accomplish it, though. Make 2 boxes, with the inner one autosized around the text, and position that inner box at the midpoint of the outer box.

There is a trick to do it with a single label. Add an transparent gif image of 1x1 pixel and set the PictureAlignment property to PicturePositionLeftCenter.

You will have to use 2 Labels.

For Example, Call them LabelBack, LabelFront. The LabelFront should be set to Opaque and No-Border Make the height of LabelFront smaller than that of LabelBack and put it over it more or less.

Then add the following code:

LabelFront.Top = (LabelBack.Top + (LabelBack.Height - LabelFront.Height) / 2) - 1

Notice, I subtracted 1 to compensate the 1 extra pixel within the LabelFront.