diff --git a/src/uu/mktemp/src/mktemp.rs b/src/uu/mktemp/src/mktemp.rs
index 491814b268d..1faf0719a89 100644
--- a/src/uu/mktemp/src/mktemp.rs
+++ b/src/uu/mktemp/src/mktemp.rs
@@ -53,9 +53,14 @@ enum MkTempError {
     /// The template suffix contains a path separator (e.g. `"XXXa/b"`).
     SuffixContainsDirSeparator(String),
     InvalidTemplate(String),
+    TooManyTemplates,
 }
 
-impl UError for MkTempError {}
+impl UError for MkTempError {
+    fn usage(&self) -> bool {
+        matches!(self, Self::TooManyTemplates)
+    }
+}
 
 impl Error for MkTempError {}
 
@@ -85,6 +90,9 @@ impl Display for MkTempError {
                 "invalid template, {}; with --tmpdir, it may not be absolute",
                 s.quote()
             ),
+            TooManyTemplates => {
+                write!(f, "too many templates")
+            }
         }
     }
 }
@@ -317,11 +325,24 @@ impl Params {
 
 #[uucore::main]
 pub fn uumain(args: impl uucore::Args) -> UResult<()> {
-    let matches = uu_app().try_get_matches_from(args)?;
+    let args = args.collect_str_lossy().accept_any();
+
+    let matches = uu_app().try_get_matches_from(&args)?;
 
     // Parse command-line options into a format suitable for the
     // application logic.
     let options = Options::from(&matches);
+
+    if env::var("POSIXLY_CORRECT").is_ok() {
+        // If POSIXLY_CORRECT was set, template MUST be the last argument.
+        if is_tmpdir_argument_actually_the_template(&matches) || matches.is_present(ARG_TEMPLATE) {
+            // Template argument was provided, check if was the last one.
+            if args.last().unwrap() != &options.template {
+                return Err(Box::new(MkTempError::TooManyTemplates));
+            }
+        }
+    }
+
     let dry_run = options.dry_run;
     let suppress_file_err = options.quiet;
     let make_dir = options.directory;
diff --git a/tests/by-util/test_mktemp.rs b/tests/by-util/test_mktemp.rs
index 7d059aeab89..db40cd7f668 100644
--- a/tests/by-util/test_mktemp.rs
+++ b/tests/by-util/test_mktemp.rs
@@ -680,3 +680,25 @@ fn test_tmpdir_env_var() {
     assert_matches_template!(template, filename);
     assert!(at.file_exists(filename));
 }
+
+#[test]
+fn test_mktemp_with_posixly_correct() {
+    let scene = TestScenario::new(util_name!());
+
+    scene
+        .ucmd()
+        .env("POSIXLY_CORRECT", "1")
+        .args(&["aXXXX", "--suffix=b"])
+        .fails()
+        .stderr_is(&format!(
+            "mktemp: too many templates\nTry '{} {} --help' for more information.\n",
+            scene.bin_path.to_string_lossy(),
+            scene.util_name
+        ));
+
+    scene
+        .ucmd()
+        .env("POSIXLY_CORRECT", "1")
+        .args(&["--suffix=b", "aXXXX"])
+        .succeeds();
+}
diff --git a/tests/by-util/test_tail.rs b/tests/by-util/test_tail.rs
index 3b809114f56..2f8ca4a7890 100644
--- a/tests/by-util/test_tail.rs
+++ b/tests/by-util/test_tail.rs
@@ -1877,10 +1877,10 @@ fn test_follow_name_move_create2() {
         "9",
     ];
 
-    let delay = 300;
+    let mut delay = 500;
     for _ in 0..2 {
         let mut p = ts.ucmd().set_stdin(Stdio::null()).args(&args).run_no_wait();
-        sleep(Duration::from_millis(100));
+        sleep(Duration::from_millis(delay));
 
         at.truncate("9", "x\n");
         sleep(Duration::from_millis(delay));
@@ -1916,6 +1916,7 @@ fn test_follow_name_move_create2() {
 
         at.remove("f");
         args.push("---disable-inotify");
+        delay = 2000;
     }
 }