diff --git a/picard/script/functions.py b/picard/script/functions.py
index c6004810c..d648b80bb 100644
--- a/picard/script/functions.py
+++ b/picard/script/functions.py
@@ -1296,3 +1296,31 @@ Result: C; B; A
 def func_reversemulti(parser, multi, separator=MULTI_VALUED_JOINER):
     multi_value = MultiValue(parser, multi, separator)
     return multi_value.separator.join(reversed(multi_value))
+
+
+@script_function(eval_args=False, documentation=N_(
+    """`$unique(name,case_sensitive="",separator="; ")`
+
+Returns a copy of the multi-value tag `name` with no duplicate elements.
+    By default, a case-insensitive comparison of the elements is performed.
+
+Example 1:
+
+    $setmulti(foo,a; A; B; b; cd; Cd; cD; CD; a; A; b)
+    $unique(%foo%)
+
+Result: A; CD; b
+
+Example 2:
+
+    $setmulti(foo,a; A; B; b; a; b; A; B, cd)
+    $unique(%foo%,True)
+
+Result: A; B; a; b; cd
+"""
+))
+def func_unique(parser, multi, case_sensitive="", separator=MULTI_VALUED_JOINER):
+    multi_value = MultiValue(parser, multi, separator)
+    if not case_sensitive:
+        multi_value._multi = list({v.lower(): v for v in multi_value}.values())
+    return multi_value.separator.join(sorted(set(multi_value)))
diff --git a/test/test_script.py b/test/test_script.py
index a719c1f0f..6265397e4 100644
--- a/test/test_script.py
+++ b/test/test_script.py
@@ -1494,3 +1494,27 @@ class ScriptParserTest(PicardTestCase):
             self.parser.eval("$reversemulti()")
         with self.assertRaisesRegex(ScriptError, areg):
             self.parser.eval("$reversemulti(B:AB; D:C; E:D; A:A; C:X,:,extra)")
+
+    def test_cmd_unique(self):
+        context = Metadata()
+        context["foo"] = ['a', 'A', 'B', 'b', 'cd', 'Cd', 'cD', 'CD', 'a', 'A', 'b']
+        context["bar"] = "a; A; B; b; cd; Cd; cD; CD; a; A; b"
+        # Tests with context
+        self.assertScriptResultEquals("$unique(%foo%)", "A; CD; b", context)
+        self.assertScriptResultEquals("$unique(%bar%)", "a; A; B; b; cd; Cd; cD; CD; a; A; b", context)
+        # Tests with static inputs
+        self.assertScriptResultEquals("$unique(a; A; B; b; cd; Cd; cD; CD; a; A; b)", "A; CD; b", context)
+        # Tests with separator override
+        self.assertScriptResultEquals("$unique(a: A: B: b: cd: Cd: cD: CD: a: A: b,,: )", "A: CD: b", context)
+        # Tests with case-sensitive comparison
+        self.assertScriptResultEquals("$unique(%foo%,1)", "A; B; CD; Cd; a; b; cD; cd", context)
+        # Tests with missing inputs
+        self.assertScriptResultEquals("$unique(,)", "", context)
+        self.assertScriptResultEquals("$unique(,,)", "", context)
+        self.assertScriptResultEquals("$unique(,:)", "", context)
+        # Tests with invalid number of arguments
+        areg = r"^\d+:\d+:\$unique: Wrong number of arguments for \$unique: Expected between 1 and 3, "
+        with self.assertRaisesRegex(ScriptError, areg):
+            self.parser.eval("$unique()")
+        with self.assertRaisesRegex(ScriptError, areg):
+            self.parser.eval("$unique(B:AB; D:C; E:D; A:A; C:X,1,:,extra)")