diff --git a/src/fish.cpp b/src/fish.cpp
index 8223a9e3e..448b4c7ca 100644
--- a/src/fish.cpp
+++ b/src/fish.cpp
@@ -318,6 +318,14 @@ static int fish_parse_opt(int argc, char **argv, std::vector<std::string> *cmds)
 /// Various things we need to initialize at run-time that don't really fit any of the other init
 /// routines.
 static void misc_init() {
+    // If stdout is open on a tty ensure stdio is unbuffered. That's because those functions might
+    // be intermixed with `write()` calls and we need to ensure the writes are not reordered. See
+    // issue #3748.
+    if (isatty(STDOUT_FILENO)) {
+        fflush(stdout);
+        setvbuf(stdout, NULL, _IONBF, 0);
+    }
+
 #ifdef OS_IS_CYGWIN
     // MS Windows tty devices do not currently have either a read or write timestamp. Those
     // respective fields of `struct stat` are always the current time. Which means we can't
diff --git a/src/reader.cpp b/src/reader.cpp
index f7228843a..a12d2b189 100644
--- a/src/reader.cpp
+++ b/src/reader.cpp
@@ -689,9 +689,6 @@ void reader_write_title(const wcstring &cmd, bool reset_cursor_position) {
         // Put the cursor back at the beginning of the line (issue #2453).
         fputwc(L'\r', stdout);
     }
-
-    // TODO: This should be removed when issue #3748 is fixed.
-    fflush(stdout);
 }
 
 /// Reexecute the prompt command. The output is inserted into data->prompt_buff.