How do I make a GUI scale with the text inside it?

There is a way, but it's kinda complicated, to do it:

1. Set the text's X alignment to left, and it's Y alignment to right.

2. Set the TextLabel's size so it fits one 'line' of text.

3. Do the following code, inside the same parent as the TextLabel.

local text = script.Parent.TextLabel -- what you resize
local maxLength = 5 -- how many characters can fit in one 'line'
local num = 0
local len = string.len(text.Text)

while len > maxLength do
    len = len - maxLength
    num = num + 1
    if len > 0 and len < maxLength then
        num = num + 1
    end
    wait()
end

text.Size = UDim2.new(text.Size.X.Scale,text.Size.X.Offset,text.Size.Y.Scale*num,text.Size.Y.Offset*num) -- resizes it, with the formula of 'size*number' making it the right size

Note, this isn't tested, so if there is something wrong, tell me. If you need more help, please ask in the comments.

Hope I helped :)

~TDP