Do you mean something like a TGroupBox or alike? Then yes, with some caveats: it might work if you just change its Color (and Font.Color) property to whatever you want, but the borders will still be drawn by the system and colored according to the theme and the same might happen with the controls inside, depending on the control.
If that doesn't work then you might be able to do it in a handler for its OnPaint event ... if the control has it! Which TGroupBox, for example, haven't.