diff --git a/implicits/src/upickle/implicits/Readers.scala b/implicits/src/upickle/implicits/Readers.scala
index a184d3379..f15c890a8 100644
--- a/implicits/src/upickle/implicits/Readers.scala
+++ b/implicits/src/upickle/implicits/Readers.scala
@@ -257,17 +257,17 @@ trait Readers extends upickle.core.Types
     }
   }
 
-  implicit def MapReader1[K, V](implicit k: Reader[K], v: Reader[V]): Reader[collection.Map[K, V]] = {
+  implicit def MapReader1[K: Reader, V: Reader]: Reader[collection.Map[K, V]] = {
     MapReader0[collection.Map, K, V](_.toMap)
   }
-  implicit def MapReader2[K, V](implicit k: Reader[K], v: Reader[V]): Reader[collection.immutable.Map[K, V]] = {
+  implicit def MapReader2[K: Reader, V: Reader]: Reader[collection.immutable.Map[K, V]] = {
     MapReader0[collection.immutable.Map, K, V]{seq =>
       val b = collection.immutable.Map.newBuilder[K, V]
       seq.foreach(b += _)
       b.result()
     }
   }
-  implicit def MapReader3[K, V](implicit k: Reader[K], v: Reader[V]): Reader[collection.mutable.Map[K, V]] = {
+  implicit def MapReader3[K: Reader, V: Reader]: Reader[collection.mutable.Map[K, V]] = {
     MapReader0[collection.mutable.Map, K, V]{seq =>
       val b = collection.mutable.Map.newBuilder[K, V]
       seq.foreach(b += _)
@@ -275,6 +275,38 @@ trait Readers extends upickle.core.Types
     }
   }
 
+  implicit def MapReader4[K: Reader, V: Reader]: Reader[collection.mutable.LinkedHashMap[K, V]] = {
+    MapReader0[collection.mutable.LinkedHashMap, K, V]{seq =>
+      val b = collection.mutable.LinkedHashMap.newBuilder[K, V]
+      seq.foreach(b += _)
+      b.result()
+    }
+  }
+
+  implicit def SortedMapReader[K: Reader: Ordering, V: Reader]: Reader[collection.mutable.SortedMap[K, V]] = {
+    MapReader0[collection.mutable.SortedMap, K, V]{seq =>
+      val b = collection.mutable.SortedMap.newBuilder[K, V]
+      seq.foreach(b += _)
+      b.result()
+    }
+  }
+
+  implicit def MapReader6[K: Reader: Ordering, V: Reader]: Reader[collection.immutable.SortedMap[K, V]] = {
+    MapReader0[collection.immutable.SortedMap, K, V]{seq =>
+      val b = collection.immutable.SortedMap.newBuilder[K, V]
+      seq.foreach(b += _)
+      b.result()
+    }
+  }
+
+  implicit def MapReader7[K: Reader: Ordering, V: Reader]: Reader[collection.SortedMap[K, V]] = {
+    MapReader0[collection.SortedMap, K, V]{seq =>
+      val b = collection.SortedMap.newBuilder[K, V]
+      seq.foreach(b += _)
+      b.result()
+    }
+  }
+
   implicit def OptionReader[T: Reader]: Reader[Option[T]] = new SimpleReader[Option[T]] {
     override def expectedMsg = "expected sequence"
     override def visitArray(length: Int, index: Int) = new ArrVisitor[Any, Option[T]] {
diff --git a/implicits/src/upickle/implicits/Writers.scala b/implicits/src/upickle/implicits/Writers.scala
index 67f1948d4..01a94b02b 100644
--- a/implicits/src/upickle/implicits/Writers.scala
+++ b/implicits/src/upickle/implicits/Writers.scala
@@ -141,18 +141,35 @@ trait Writers extends upickle.core.Types
     }
   }
 
-  implicit def MapWriter1[K, V](implicit kw: Writer[K], vw: Writer[V]): Writer[collection.Map[K, V]] = {
+  implicit def MapWriter1[K: Writer, V: Writer]: Writer[collection.Map[K, V]] = {
     MapWriter0[collection.Map, K, V]
   }
 
-  implicit def MapWriter2[K, V](implicit kw: Writer[K], vw: Writer[V]): Writer[collection.immutable.Map[K, V]] = {
+  implicit def MapWriter2[K: Writer, V: Writer]: Writer[collection.immutable.Map[K, V]] = {
     MapWriter0[collection.immutable.Map, K, V]
   }
 
-  implicit def MapWriter3[K, V](implicit kw: Writer[K], vw: Writer[V]): Writer[collection.mutable.Map[K, V]] = {
+  implicit def MapWriter3[K: Writer, V: Writer]: Writer[collection.mutable.Map[K, V]] = {
     MapWriter0[collection.mutable.Map, K, V]
   }
 
+  implicit def MapWriter4[K: Writer, V: Writer]: Writer[collection.mutable.LinkedHashMap[K, V]] = {
+    MapWriter0[collection.mutable.LinkedHashMap, K, V]
+  }
+
+  implicit def MapWriter5[K: Writer, V: Writer]: Writer[collection.mutable.SortedMap[K, V]] = {
+    MapWriter0[collection.mutable.SortedMap, K, V]
+  }
+
+  implicit def MapWriter6[K: Writer, V: Writer]: Writer[collection.immutable.SortedMap[K, V]] = {
+    MapWriter0[collection.immutable.SortedMap, K, V]
+  }
+
+
+  implicit def MapWriter7[K: Writer, V: Writer]: Writer[collection.SortedMap[K, V]] = {
+    MapWriter0[collection.SortedMap, K, V]
+  }
+
   implicit val DurationWriter: Writer[Duration] = new SimpleMapKeyWriter[Duration]{
     override def writeString(v: Duration) = v match{
       case Duration.Inf => "inf"
diff --git a/upickle/test/src/upickle/StructTests.scala b/upickle/test/src/upickle/StructTests.scala
index 3c349def0..24e7e4d26 100644
--- a/upickle/test/src/upickle/StructTests.scala
+++ b/upickle/test/src/upickle/StructTests.scala
@@ -384,6 +384,63 @@ object StructTests extends TestSuite {
           upack.Arr(upack.Arr(upack.Str("abc"), upack.Str("def")))
         )
       }
+
+      test("variants"){
+        test("LinkedHashMap") - rw(
+          scala.collection.mutable.LinkedHashMap("Hello" -> List(1), "World" -> List(1, 2, 3)),
+          """{"Hello":[1],"World":[1,2,3]}""",
+          """[["Hello",[1]],["World",[1,2,3]]]""",
+          upack.Obj(
+            upack.Str("Hello") -> upack.Arr(upack.Int32(1)),
+            upack.Str("World") -> upack.Arr(upack.Int32(1), upack.Int32(2), upack.Int32(3))
+          ),
+          upack.Arr(
+            upack.Arr(upack.Str("Hello"), upack.Arr(upack.Int32(1))),
+            upack.Arr(upack.Str("World"), upack.Arr(upack.Int32(1), upack.Int32(2), upack.Int32(3)))
+          )
+        )
+        test("SortedMap"){
+          test("immutable") - rw(
+            scala.collection.immutable.SortedMap("Hello" -> List(1), "World" -> List(1, 2, 3)),
+            """{"Hello":[1],"World":[1,2,3]}""",
+            """[["Hello",[1]],["World",[1,2,3]]]""",
+            upack.Obj(
+              upack.Str("Hello") -> upack.Arr(upack.Int32(1)),
+              upack.Str("World") -> upack.Arr(upack.Int32(1), upack.Int32(2), upack.Int32(3))
+            ),
+            upack.Arr(
+              upack.Arr(upack.Str("Hello"), upack.Arr(upack.Int32(1))),
+              upack.Arr(upack.Str("World"), upack.Arr(upack.Int32(1), upack.Int32(2), upack.Int32(3)))
+            )
+          )
+          test("mutable") - rw(
+            scala.collection.mutable.SortedMap("Hello" -> List(1), "World" -> List(1, 2, 3)),
+            """{"Hello":[1],"World":[1,2,3]}""",
+            """[["Hello",[1]],["World",[1,2,3]]]""",
+            upack.Obj(
+              upack.Str("Hello") -> upack.Arr(upack.Int32(1)),
+              upack.Str("World") -> upack.Arr(upack.Int32(1), upack.Int32(2), upack.Int32(3))
+            ),
+            upack.Arr(
+              upack.Arr(upack.Str("Hello"), upack.Arr(upack.Int32(1))),
+              upack.Arr(upack.Str("World"), upack.Arr(upack.Int32(1), upack.Int32(2), upack.Int32(3)))
+            )
+          )
+          test("collection") - rw(
+            scala.collection.SortedMap("Hello" -> List(1), "World" -> List(1, 2, 3)),
+            """{"Hello":[1],"World":[1,2,3]}""",
+            """[["Hello",[1]],["World",[1,2,3]]]""",
+            upack.Obj(
+              upack.Str("Hello") -> upack.Arr(upack.Int32(1)),
+              upack.Str("World") -> upack.Arr(upack.Int32(1), upack.Int32(2), upack.Int32(3))
+            ),
+            upack.Arr(
+              upack.Arr(upack.Str("Hello"), upack.Arr(upack.Int32(1))),
+              upack.Arr(upack.Str("World"), upack.Arr(upack.Int32(1), upack.Int32(2), upack.Int32(3)))
+            )
+          )
+        }
+      }
     }
 
     test("option"){