By default, Tkinter widgets will resize based on their children's sizes (i.e., Tkinter will not respect my width and height configurations). I know that using parent.pack_propagate(False) will prevent parent's children from modifying its dimensions, but what if I only want to prevent the children from changing one dimension, allowing it to modify another dimension? For example, how would I prevent a widget's children from modifying its width but allow it to change its height?
One hack-ish solution I came up with was to have a 1px tall frame with my requested width and add that to the parent, which prevented the other children from shrinking the width of the parent, but this seems like an inelegant solution. Is there any built-in solution to this?
No, there is no way to constrain the geometry propagation in only one direction. 
In my experience there are almost always better ways to solve layout problems than turning propagation off. There is no single best solution, it all depends on your specific layout needs.
Tkinter - Prevent children from changing parent width