diff --git a/src/Lean/Elab/Syntax.lean b/src/Lean/Elab/Syntax.lean
index 0cc869d58b98..d13cc3de4d29 100644
--- a/src/Lean/Elab/Syntax.lean
+++ b/src/Lean/Elab/Syntax.lean
@@ -242,7 +242,7 @@ where
   processAtom (stx : Syntax) := do
     match stx[0].isStrLit? with
     | some atom =>
-      unless isValidAtom atom do
+      unless isValidAtom atom.trim do
         throwErrorAt stx "invalid atom"
       /- For syntax categories where initialized with `LeadingIdentBehavior` different from default (e.g., `tactic`), we automatically mark
          the first symbol as nonReserved. -/
diff --git a/tests/lean/242.lean b/tests/lean/242.lean
index df964c9236d3..56d5698371a8 100644
--- a/tests/lean/242.lean
+++ b/tests/lean/242.lean
@@ -2,3 +2,7 @@ syntax "0" : term
 syntax "'a'" : term
 syntax "`a" : term
 syntax "\"a" : term
+syntax " 0" : term
+syntax " 'a'" : term
+syntax " `a" : term
+syntax " \"a" : term
diff --git a/tests/lean/242.lean.expected.out b/tests/lean/242.lean.expected.out
index 70de8ea84b87..39f7550ca2de 100644
--- a/tests/lean/242.lean.expected.out
+++ b/tests/lean/242.lean.expected.out
@@ -2,3 +2,7 @@
 242.lean:2:7-2:12: error: invalid atom
 242.lean:3:7-3:11: error: invalid atom
 242.lean:4:7-4:12: error: invalid atom
+242.lean:5:7-5:11: error: invalid atom
+242.lean:6:7-6:13: error: invalid atom
+242.lean:7:7-7:12: error: invalid atom
+242.lean:8:7-8:13: error: invalid atom