Display Screen or Portion Thereof with Graphical User Interface

FIG. 1 is a front view of a display screen or portion thereof with a graphical user interface showing the claimed design according to a first embodiment. FIG. 2 is a front view of a display screen or portion thereof with a graphical user interface showing the claimed design according to a second embodiment. FIG. 3 is a front view of a display screen or portion thereof with a graphical user interface showing the claimed design according to a third embodiment. FIG. 4 is a front view of a display screen or portion thereof with a graphical user interface showing the claimed design according to a fourth embodiment; and, FIG. 5 is a front view of a display screen or portion thereof with a graphical user interface showing the claimed design according to a fifth embodiment. The outermost broken-line border in the figures shows the perimeter of a display screen or portion thereof and forms no part of the claimed design. The remaining broken lines illustrate features of a graphical user interface and form no part of the claimed design.