diff --git a/lib/commands/ls.js b/lib/commands/ls.js
index ac0f4817efec8..2f9c7fca4729c 100644
--- a/lib/commands/ls.js
+++ b/lib/commands/ls.js
@@ -80,6 +80,7 @@ class LS extends ArboristWorkspaceCmd {
     const filterBySelectedWorkspaces = edge => {
       if (!workspacesEnabled
         && edge.from.isProjectRoot
+        && edge.to
         && edge.to.isWorkspace
       ) {
         return false
diff --git a/tap-snapshots/test/lib/commands/ls.js.test.cjs b/tap-snapshots/test/lib/commands/ls.js.test.cjs
index 5ceb233215fc4..f3ce81d65383f 100644
--- a/tap-snapshots/test/lib/commands/ls.js.test.cjs
+++ b/tap-snapshots/test/lib/commands/ls.js.test.cjs
@@ -549,6 +549,12 @@ test-npm-ls@1.0.0 {CWD}/prefix
   \`-- dog@1.0.0
 `
 
+exports[`test/lib/commands/ls.js TAP ls no workspaces and missing optional dep > should list missing optional dep and omit workspaces 1`] = `
+root@ {CWD}/prefix
++-- UNMET OPTIONAL DEPENDENCY bar@^1.0.0
+\`-- foo@1.0.0
+`
+
 exports[`test/lib/commands/ls.js TAP ls overridden dep > should contain overridden output 1`] = `
 test-overridden@1.0.0 {CWD}/prefix
 \`-- foo@1.0.0
diff --git a/test/lib/commands/ls.js b/test/lib/commands/ls.js
index 9f97d33f8d9ca..f8eb8e011c0b9 100644
--- a/test/lib/commands/ls.js
+++ b/test/lib/commands/ls.js
@@ -205,6 +205,45 @@ t.test('ls', async t => {
     t.matchSnapshot(cleanCwd(result()), 'should omit missing optional dep')
   })
 
+  t.test('no workspaces and missing optional dep', async t => {
+    const config = {
+      workspaces: false,
+    }
+    const { result, ls } = await mockLs(t, {
+      config,
+      prefixDir: {
+        'package.json': JSON.stringify({
+          name: 'root',
+          dependencies: {
+            foo: '^1.0.0',
+          },
+          optionalDependencies: {
+            bar: '^1.0.0',
+          },
+          workspaces: ['./baz'],
+        }),
+        baz: {
+          'package.json': JSON.stringify({
+            name: 'baz',
+            version: '1.0.0',
+          }),
+        },
+        node_modules: {
+          baz: t.fixture('symlink', '../baz'),
+          foo: {
+            'package.json': JSON.stringify({
+              name: 'foo',
+              version: '1.0.0',
+            }),
+          },
+        },
+      },
+    })
+
+    await ls.exec([])
+    t.matchSnapshot(cleanCwd(result()), 'should list missing optional dep and omit workspaces')
+  })
+
   t.test('extraneous deps', async t => {
     const { result, ls } = await mockLs(t, {
       config: {},