A new and distinct Hosta plant named ‘School Mouse’ with coarsely-sinuate cordate leaf blades having variegation of creamy yellow margins and dark green center and feathering intermediate colors. The plant habit is short, compact and rounded with flowering just above foliage, and the leaves and scapes are thick substance and stiff, flowering just above the foliage with medium lavender flowers with strongly veined deep lavender and white insides.
