diff --git a/src/builtins/echo.rs b/src/builtins/echo.rs
index 837807af7..51af381c9 100644
--- a/src/builtins/echo.rs
+++ b/src/builtins/echo.rs
@@ -110,7 +110,7 @@ fn parse_numeric_sequence<I>(chars: I) -> Option<(usize, u8)>
         return None;
     }
 
-    let mut val = 0;
+    let mut val: u8 = 0;
     let mut consumed = start;
     for digit in chars
         .skip(start)
@@ -120,7 +120,7 @@ fn parse_numeric_sequence<I>(chars: I) -> Option<(usize, u8)>
         // base is either 8 or 16, so digit can never be >255
         let digit = u8::try_from(digit).unwrap();
 
-        val = val * base + digit;
+        val = val.wrapping_mul(base).wrapping_add(digit);
 
         consumed += 1;
     }
diff --git a/tests/checks/basic.fish b/tests/checks/basic.fish
index fb07342a6..5bef45cc8 100644
--- a/tests/checks/basic.fish
+++ b/tests/checks/basic.fish
@@ -143,6 +143,11 @@ echo -e 'abc\121def'
 echo -e 'abc\1212def'
 #CHECK: abcQdef
 #CHECK: abcQ2def
+# Test octal overflow: \5555 = 555 octal = 365 decimal, wraps to 109 decimal (155 octal)
+# Followed by literal '5' character (065 octal)
+echo -ne '\5555' | display_bytes
+#CHECK: 0000000 155 065
+#CHECK: 0000002
 echo -e 'abc\cdef' # won't output a newline!
 #CHECK: abc
 echo ''