diff --git a/src/test/system/list_formatting_test.js b/src/test/system/list_formatting_test.js
index 3d3ab7c05..749110548 100644
--- a/src/test/system/list_formatting_test.js
+++ b/src/test/system/list_formatting_test.js
@@ -96,6 +96,38 @@ testGroup("List formatting", { template: "editor_empty" }, () => {
     expectDocument("ab\nc\n")
   })
 
+  test("increasing nesting level applies to all selected items", async () => {
+    await clickToolbarButton({ attribute: "bullet" })
+    await typeCharacters("a\nb\nc")
+    getSelectionManager().setLocationRange([
+      { index: 0, offset: 0 },
+      { index: 2, offset: 1 },
+    ])
+    await clickToolbarButton({ action: "increaseNestingLevel" })
+    assert.blockAttributes([ 0, 2 ], [ "bulletList", "bullet", "bulletList", "bullet" ])
+    assert.blockAttributes([ 2, 4 ], [ "bulletList", "bullet", "bulletList", "bullet" ])
+    assert.blockAttributes([ 4, 6 ], [ "bulletList", "bullet", "bulletList", "bullet" ])
+    expectDocument("a\nb\nc\n")
+  })
+
+  test("decreasing nesting level applies to all selected items", async () => {
+    await clickToolbarButton({ attribute: "bullet" })
+    await typeCharacters("a\n")
+    await clickToolbarButton({ action: "increaseNestingLevel" })
+    await typeCharacters("b\n")
+    await clickToolbarButton({ action: "increaseNestingLevel" })
+    await typeCharacters("c")
+    getSelectionManager().setLocationRange([
+      { index: 1, offset: 0 },
+      { index: 2, offset: 1 },
+    ])
+    await clickToolbarButton({ action: "decreaseNestingLevel" })
+    assert.blockAttributes([ 0, 2 ], [ "bulletList", "bullet" ])
+    assert.blockAttributes([ 2, 4 ], [ "bulletList", "bullet" ])
+    assert.blockAttributes([ 4, 6 ], [ "bulletList", "bullet", "bulletList", "bullet" ])
+    expectDocument("a\nb\nc\n")
+  })
+
   test("decreasing list item's level decreases its nested items level too", async () => {
     await clickToolbarButton({ attribute: "bullet" })
     await typeCharacters("a\n")
diff --git a/src/trix/models/composition.js b/src/trix/models/composition.js
index ad61bb358..1bc760a5d 100644
--- a/src/trix/models/composition.js
+++ b/src/trix/models/composition.js
@@ -415,15 +415,33 @@ export default class Composition extends BasicObject {
   }
 
   decreaseNestingLevel() {
-    const block = this.getBlock()
-    if (!block) return
-    return this.setDocument(this.document.replaceBlock(block, block.decreaseNestingLevel()))
+    const locationRange = this.getLocationRange()
+    if (!locationRange) return
+    const startIndex = locationRange[0].index
+    const endIndex = locationRange[1].offset === 0 && locationRange[1].index > startIndex
+      ? locationRange[1].index - 1
+      : locationRange[1].index
+    let document = this.document
+    for (let i = startIndex; i <= endIndex; i++) {
+      const block = document.getBlockAtIndex(i)
+      if (block) document = document.replaceBlock(block, block.decreaseNestingLevel())
+    }
+    return this.setDocument(document)
   }
 
   increaseNestingLevel() {
-    const block = this.getBlock()
-    if (!block) return
-    return this.setDocument(this.document.replaceBlock(block, block.increaseNestingLevel()))
+    const locationRange = this.getLocationRange()
+    if (!locationRange) return
+    const startIndex = locationRange[0].index
+    const endIndex = locationRange[1].offset === 0 && locationRange[1].index > startIndex
+      ? locationRange[1].index - 1
+      : locationRange[1].index
+    let document = this.document
+    for (let i = startIndex; i <= endIndex; i++) {
+      const block = document.getBlockAtIndex(i)
+      if (block) document = document.replaceBlock(block, block.increaseNestingLevel())
+    }
+    return this.setDocument(document)
   }
 
   canDecreaseBlockAttributeLevel() {