diff --git a/CHANGELOG.md b/CHANGELOG.md
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -3,10 +3,17 @@
 `language-asn` uses [PVP Versioning][1].
 The changelog is available [on GitHub][2].
 
-0.0.0
-=====
+0.1.1.0
+=======
 
-* Initially created.
+* Added `FromJSON`, `FromJSONKey`, and `ToJSON` instances to
+  `ObjectIdentifier`.
+
+0.1.0.0
+=======
+
+* Moved all ASN.1 code from the now-deprecated `asn1-codec` into
+  this library.
 
 [1]: https://pvp.haskell.org
 [2]: https://github.com/chessai/language-asn/releases
diff --git a/language-asn.cabal b/language-asn.cabal
--- a/language-asn.cabal
+++ b/language-asn.cabal
@@ -2,11 +2,11 @@
 name:
   language-asn
 version:
-  0.1.0.0
+  0.1.1.0
 synopsis:
   ASN.1 encoding and decoding
 description:
-  ASN.1 language implementation. ASN.1 is used tightly with SNMP.
+  ASN.1 language implementation. SNMP uses ASN.1 for serialization.
 homepage:
   https://github.com/chessai/language-asn.git
 license:
@@ -32,20 +32,21 @@
 
 library
   exposed-modules:
-    Language.Asn.Encoding
     Language.Asn.Decoding
+    Language.Asn.Encoding
     Language.Asn.ObjectIdentifier
     Language.Asn.Types
     Language.Asn.Types.Internal
   build-depends:
-      base >=4.9 && <4.13
+    , aeson >= 1.2 && < 1.5
+    , base >=4.9 && <4.13
     , bytestring >= 0.10 && < 0.11
     , contravariant >= 1.3 && < 1.6
-    , vector >= 0.11 && < 0.13
-    , primitive >= 0.6.4 && < 7
+    , hashable >= 1.2 && < 1.3
     , pretty >= 1.1 && < 1.2
+    , primitive >= 0.6.4 && < 7
     , text >= 1.2 && < 1.3
-    , hashable >= 1.2 && < 1.3
+    , vector >= 0.11 && < 0.13
   hs-source-dirs:
     src
   default-language:
diff --git a/src/Language/Asn/Types/Internal.hs b/src/Language/Asn/Types/Internal.hs
--- a/src/Language/Asn/Types/Internal.hs
+++ b/src/Language/Asn/Types/Internal.hs
@@ -14,22 +14,31 @@
 module Language.Asn.Types.Internal where
 
 import Prelude hiding (sequence,null)
-import Data.String (IsString)
+
+import Data.Aeson (ToJSON,FromJSON,FromJSONKey)
 import Data.ByteString (ByteString)
-import Data.Text (Text)
-#if !MIN_VERSION_base(4,11,0)
-import Data.Monoid (Monoid)
-#endif
-import Data.Semigroup (Semigroup)
-import Data.Word
-import Data.Primitive (PrimArray)
-import GHC.Int (Int(..))
+import Data.Functor.Contravariant (Contravariant(..))
 import Data.Hashable (Hashable(..))
+import Data.Primitive (PrimArray)
+import Data.Semigroup (Semigroup)
+import Data.String (IsString)
+import Data.Text (Text)
+import Data.Word (Word64,Word8)
 import GHC.Generics (Generic)
-import Data.Functor.Contravariant (Contravariant(..))
+import GHC.Int (Int(..))
+
+import qualified Data.Aeson as AE
+import qualified Data.Aeson.Types as AE
 import qualified Data.ByteString.Lazy as LB
+import qualified Data.List as L
+import qualified Data.Text as T
+import qualified Data.Text.Read as TR
 import qualified GHC.Exts as E
 
+#if !MIN_VERSION_base(4,11,0)
+import Data.Monoid (Monoid)
+#endif
+
 data AsnEncoding a
   = EncSequence [Field a]
   | forall b. EncSequenceOf (a -> [b]) (AsnEncoding b)
@@ -74,6 +83,30 @@
 newtype ObjectIdentifier = ObjectIdentifier
   { getObjectIdentifier :: PrimArray Word
   } deriving (Eq,Ord,Show,Generic)
+
+instance ToJSON ObjectIdentifier where
+  toJSON (ObjectIdentifier xs) = AE.toJSON
+    $ mconcat
+    $ L.intersperse (T.singleton '.')
+    $ map (T.pack . show)
+    $ E.toList xs
+
+instance FromJSONKey ObjectIdentifier where
+  fromJSONKey = AE.FromJSONKeyTextParser oidJsonParser
+
+instance FromJSON ObjectIdentifier where
+  parseJSON = AE.withText "ObjectIdentifier" oidJsonParser
+
+oidJsonParser :: Text -> AE.Parser ObjectIdentifier
+oidJsonParser t =
+  case fmap (ObjectIdentifier . E.fromList) (mapM parseWord (T.splitOn (T.singleton '.') t)) of
+    Nothing -> fail ("could not recognize " ++ T.unpack t ++ " as an OID")
+    Just x -> return x
+
+parseWord :: Text -> Maybe Word
+parseWord t = case TR.decimal t of
+  Right (i,leftovers) -> if T.null leftovers then Just i else Nothing
+  Left _ -> Nothing
 
 instance Hashable ObjectIdentifier where
   hash (ObjectIdentifier v) = hash (E.toList v)