diff --git a/build.sbt b/build.sbt
index 4ab56c21..18f3d33a 100644
--- a/build.sbt
+++ b/build.sbt
@@ -107,7 +107,6 @@ lazy val commonSettings = Seq(
 
   // uncomment in case of emergency
   // scalacOptions ++= { if (scalaVersion.value.startsWith("3.")) Seq("-source:3.0-migration") else Nil },
-
 )
 
 lazy val skunk = tlCrossRootProject
@@ -200,6 +199,7 @@ lazy val tests = crossProject(JVMPlatform, JSPlatform, NativePlatform)
     }
   )
   .jsSettings(
+    scalaJSLinkerConfig ~= { _.withESFeatures(_.withESVersion(org.scalajs.linker.interface.ESVersion.ES2018)) },
     Test / scalaJSLinkerConfig ~= (_.withModuleKind(ModuleKind.CommonJSModule)),
   )
   .nativeEnablePlugins(ScalaNativeBrewedConfigPlugin)
diff --git a/docker-compose.yml b/docker-compose.yml
index 4e7361fc..7cc8903c 100644
--- a/docker-compose.yml
+++ b/docker-compose.yml
@@ -6,6 +6,7 @@ services:
     command: -c ssl=on -c ssl_cert_file=/var/lib/postgresql/server.crt -c ssl_key_file=/var/lib/postgresql/server.key
     volumes:
       - ./world/world.sql:/docker-entrypoint-initdb.d/world.sql
+      - ./world/ltree.sql:/docker-entrypoint-initdb.d/ltree.sql
       - ./world/server.crt:/var/lib/postgresql/server.crt
       - ./world/server.key:/var/lib/postgresql/server.key
     ports:
diff --git a/modules/core/shared/src/main/scala/codec/AllCodecs.scala b/modules/core/shared/src/main/scala/codec/AllCodecs.scala
index ab0dd11e..7f234211 100644
--- a/modules/core/shared/src/main/scala/codec/AllCodecs.scala
+++ b/modules/core/shared/src/main/scala/codec/AllCodecs.scala
@@ -12,5 +12,6 @@ trait AllCodecs
      with EnumCodec
      with UuidCodec
      with BinaryCodecs
+     with LTreeCodec
 
 object all extends AllCodecs
diff --git a/modules/core/shared/src/main/scala/codec/LTreeCodec.scala b/modules/core/shared/src/main/scala/codec/LTreeCodec.scala
new file mode 100644
index 00000000..d54babfb
--- /dev/null
+++ b/modules/core/shared/src/main/scala/codec/LTreeCodec.scala
@@ -0,0 +1,22 @@
+// Copyright (c) 2018-2021 by Rob Norris
+// This software is licensed under the MIT License (MIT).
+// For more information see LICENSE or https://opensource.org/licenses/MIT
+
+package skunk
+package codec
+
+import skunk.data.Type
+import skunk.data.LTree
+
+trait LTreeCodec {
+
+  val ltree: Codec[LTree] =
+    Codec.simple[LTree](
+      ltree => ltree.toString(),
+      s => LTree.fromString(s),
+      Type("ltree")
+    )
+
+}
+
+object ltree extends LTreeCodec
\ No newline at end of file
diff --git a/modules/core/shared/src/main/scala/data/LTree.scala b/modules/core/shared/src/main/scala/data/LTree.scala
new file mode 100644
index 00000000..f81df6a7
--- /dev/null
+++ b/modules/core/shared/src/main/scala/data/LTree.scala
@@ -0,0 +1,59 @@
+// Copyright (c) 2018-2021 by Rob Norris
+// This software is licensed under the MIT License (MIT).
+// For more information see LICENSE or https://opensource.org/licenses/MIT
+
+package skunk.data
+
+import cats.Eq
+
+sealed abstract case class LTree (labels: List[String]) {
+
+  def isAncestorOf(other: LTree): Boolean =
+    other.labels.startsWith(labels)
+
+  def isDescendantOf(other: LTree): Boolean = other.isAncestorOf(this)
+
+  override def toString: String = labels.mkString(LTree.Separator.toString())
+}
+
+object LTree {
+  val Empty = new LTree(Nil) {}
+
+  def fromLabels(s: String*): Either[String, LTree] =
+    fromString(s.toList.mkString(Separator.toString()))
+
+  def fromString(s: String): Either[String, LTree] = {
+
+    if (s.isEmpty()) {
+      Right(new LTree(Nil){})
+    } else {
+      // We have a failure sentinal and a helper to set it.
+      var failure: String = null
+      def fail(msg: String): Unit =
+        failure = s"ltree parse error: $msg"
+
+      val labels = s.split(Separator).toList
+
+      if(labels.length > MaxTreeLength)
+        fail(s"ltree size (${labels.size}) must be <= $MaxTreeLength")
+
+      labels.foreach(l => l match {
+        case ValidLabelRegex() => ()
+        case _ => fail(s"invalid ltree label '$l'. Only alphanumeric characters and '_' are allowed.")
+      })
+
+      if(failure != null)
+        Left(failure)
+      else
+        Right(new LTree(labels){})
+    }
+  }
+
+  final val MaxLabelLength = 255
+  final val MaxTreeLength = 65535
+
+  private final val Separator = '.'
+  private final val ValidLabelRegex = s"""^[\\p{L}0-9_]{1,$MaxLabelLength}$$""".r
+
+  implicit val ltreeEq: Eq[LTree] = Eq.fromUniversalEquals[LTree]
+}
diff --git a/modules/docs/src/main/paradox/reference/SchemaTypes.md b/modules/docs/src/main/paradox/reference/SchemaTypes.md
index 75e25b1c..e510d1ce 100644
--- a/modules/docs/src/main/paradox/reference/SchemaTypes.md
+++ b/modules/docs/src/main/paradox/reference/SchemaTypes.md
@@ -203,6 +203,12 @@ Postgres arrays are either empty and zero-dimensional, or non-empty and rectangu
 | `_bpchar`  | `Arr[String]` | Length argument not yet supported |
 | `_text`    | `Arr[String]` |  |
 
+## ltree Types
+
+| ANSI SQL Type      | Postgres Type   | Scala Type   |
+|--------------------|-----------------|--------------|
+| n/a                | `ltree`         | `LTree`      |
+
 #### Notes
 
 - See [§8.15](https://www.postgresql.org/docs/11/arrays.html) in the Postgres documentation for more information on JSON data types.
diff --git a/modules/tests/shared/src/test/scala/codec/LTreeCodecTest.scala b/modules/tests/shared/src/test/scala/codec/LTreeCodecTest.scala
new file mode 100644
index 00000000..64f63cbd
--- /dev/null
+++ b/modules/tests/shared/src/test/scala/codec/LTreeCodecTest.scala
@@ -0,0 +1,20 @@
+// Copyright (c) 2018-2021 by Rob Norris
+// This software is licensed under the MIT License (MIT).
+// For more information see LICENSE or https://opensource.org/licenses/MIT
+
+package tests
+package codec
+import skunk.codec.all._
+import skunk.data.LTree
+import skunk.util.Typer
+
+class LTreeCodecTest extends CodecTest(strategy = Typer.Strategy.SearchPath) {
+
+  roundtripTest(ltree)(LTree.Empty)
+  roundtripTest(ltree)(LTree.fromLabels("abc", "def").toOption.get)
+  roundtripTest(ltree)(LTree.fromLabels("abcdefghijklmnopqrstuvwxyz0123456789".toList.map(_.toString()) :_*).toOption.get)
+  roundtripTest(ltree)(LTree.fromString("foo.βar.baz").toOption.get)
+
+}
+
+
diff --git a/modules/tests/shared/src/test/scala/data/LTreeTest.scala b/modules/tests/shared/src/test/scala/data/LTreeTest.scala
new file mode 100644
index 00000000..96f299c8
--- /dev/null
+++ b/modules/tests/shared/src/test/scala/data/LTreeTest.scala
@@ -0,0 +1,45 @@
+// Copyright (c) 2018-2021 by Rob Norris
+// This software is licensed under the MIT License (MIT).
+// For more information see LICENSE or https://opensource.org/licenses/MIT
+
+package tests
+package data
+
+import skunk.data.LTree
+
+class LTreeTest extends ffstest.FTest {
+
+  lazy val foo = LTree.fromLabels("foo").toOption.get
+  lazy val foobar = LTree.fromLabels("foo", "bar").toOption.get
+
+  test("LTree parsing") {
+    assertEquals(LTree.fromString("").getOrElse(fail("Failed to parse empty LTree")), LTree.Empty)
+
+    assert(LTree.fromString("abc.d!f").isLeft, "regex failed")
+    assert(LTree.fromString("abc.d_f").isRight, "regex failed")
+    assert(LTree.fromString("abc1.d_f2").isRight, "regex failed")
+    assert(LTree.fromString("foo.βar.baΣΩ").isRight, "regex failed")
+    assert(LTree.fromString("foo.βar.❤").isLeft, "regex failed")
+
+    assert(LTree.fromString(List.fill(LTree.MaxTreeLength)("a").mkString(".")).isRight, "max tree len failed")
+    assert(LTree.fromString(List.fill(LTree.MaxTreeLength + 1)("a").mkString(".")).isLeft, "max tree len failed")
+
+    assert(LTree.fromString(List.fill(3)("a" * LTree.MaxLabelLength).mkString(".")).isRight, "max label len failed")
+    assert(LTree.fromString(List.fill(3)("a" * LTree.MaxLabelLength + 1).mkString(".")).isLeft, "max label len failed")
+  }
+
+  test("LTree.isAncestorOf") {
+    assert(LTree.Empty.isAncestorOf(foo))
+    assert(foo.isAncestorOf(foo))
+    assert(foo.isAncestorOf(foobar))
+
+    assert(!foo.isAncestorOf(LTree.Empty))
+    assert(!foobar.isAncestorOf(foo))
+  }
+
+  test("LTree.isDescendantOf") {
+    assert(foo.isDescendantOf(LTree.Empty))
+    assert(foobar.isDescendantOf(foo))
+  }
+
+}
diff --git a/world/ltree.sql b/world/ltree.sql
new file mode 100644
index 00000000..892ef98e
--- /dev/null
+++ b/world/ltree.sql
@@ -0,0 +1 @@
+CREATE EXTENSION ltree ;
\ No newline at end of file