diff --git a/zircon/system/ulib/fidl/BUILD.zircon.gn b/zircon/system/ulib/fidl/BUILD.zircon.gn
index 50deb0e..4ecb04e 100644
--- a/zircon/system/ulib/fidl/BUILD.zircon.gn
+++ b/zircon/system/ulib/fidl/BUILD.zircon.gn
@@ -88,8 +88,6 @@
       "lib/fidl/llcpp/client.h",
       "lib/fidl/llcpp/coding.h",
       "lib/fidl/llcpp/connect_service.h",
-      "lib/fidl/llcpp/decoded_message.h",
-      "lib/fidl/llcpp/encoded_message.h",
       "lib/fidl/llcpp/envelope.h",
       "lib/fidl/llcpp/errors.h",
       "lib/fidl/llcpp/failover_allocator.h",
diff --git a/zircon/system/ulib/fidl/include/lib/fidl/llcpp/decoded_message.h b/zircon/system/ulib/fidl/include/lib/fidl/llcpp/decoded_message.h
deleted file mode 100644
index 9918ac5..0000000
--- a/zircon/system/ulib/fidl/include/lib/fidl/llcpp/decoded_message.h
+++ /dev/null
@@ -1,115 +0,0 @@
-// Copyright 2018 The Fuchsia Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-#ifndef LIB_FIDL_LLCPP_DECODED_MESSAGE_H_
-#define LIB_FIDL_LLCPP_DECODED_MESSAGE_H_
-
-#include <lib/fidl/coding.h>
-#include <lib/fidl/llcpp/encoded_message.h>
-#include <lib/fidl/llcpp/traits.h>
-#include <zircon/assert.h>
-#include <zircon/fidl.h>
-
-#include <type_traits>
-
-namespace fidl {
-
-template <typename FidlType>
-struct DecodeResult;
-
-template <typename FidlType>
-DecodeResult<FidlType> Decode(EncodedMessage<FidlType> msg);
-
-template <typename FidlType>
-struct EncodeResult;
-
-template <typename FidlType>
-class DecodedMessage;
-
-template <typename FidlType>
-EncodeResult<FidlType> Encode(DecodedMessage<FidlType> msg);
-
-// `DecodedMessage` manages a linearized FIDL message in decoded form.
-// It takes care of releasing all handles which were not consumed
-// (std::moved from the decoded FIDL struct) when it goes out of scope.
-template <typename FidlType>
-class DecodedMessage final {
-  static_assert(IsFidlType<FidlType>::value, "Only FIDL types allowed here");
-  static_assert(FidlType::PrimarySize > 0, "Positive message size");
-
- public:
-  // Instantiates an empty message.
-  // To populate this message, decode from an EncodedMessage object.
-  DecodedMessage() = default;
-
-  // Instantiates a DecodedMessage which points to a buffer region with caller-managed memory.
-  // The buffer region is assumed to contain a linearized FIDL message with valid pointers.
-  // This does not take ownership of that buffer region.
-  // But it does take ownership of the handles within the buffer.
-  explicit DecodedMessage(BytePart bytes) : bytes_(std::move(bytes)) {
-    ZX_DEBUG_ASSERT(FidlIsAligned(bytes_.data()));
-    ZX_DEBUG_ASSERT(bytes_.actual() >= FidlAlign(FidlType::PrimarySize));
-    ZX_DEBUG_ASSERT(bytes_.actual() % FIDL_ALIGNMENT == 0);
-  }
-
-  DecodedMessage(DecodedMessage&& other) = default;
-
-  DecodedMessage& operator=(DecodedMessage&& other) = default;
-
-  DecodedMessage(const DecodedMessage& other) = delete;
-
-  DecodedMessage& operator=(const DecodedMessage& other) = delete;
-
-  ~DecodedMessage() { CloseHandles(); }
-
-  BytePart& bytes() { return bytes_; }
-
-  // Keeps track of a new buffer region with caller-managed memory.
-  // The buffer region is assumed to contain a linearized FIDL message with valid pointers.
-  // This does not take ownership of that buffer region.
-  // But it does take ownership of the handles within the buffer.
-  void Reset(BytePart bytes) {
-    CloseHandles();
-    bytes_ = std::move(bytes);
-  }
-
-  // Returns ownership of the buffer and handles contained within to the caller.
-  BytePart Release() {
-    fidl::BytePart released_bytes = std::move(bytes_);
-    return released_bytes;
-  }
-
-  // Accesses the FIDL message by reinterpreting the buffer pointer.
-  // Returns nullptr if there is no message.
-  FidlType* message() const { return reinterpret_cast<FidlType*>(bytes_.data()); }
-
-  // Returns true iff the DecodedMessage has a valid message, i.e. non-NULL buffer pointer.
-  bool is_valid() const { return bytes_.data() != nullptr; }
-
- private:
-  friend DecodeResult<FidlType> Decode<FidlType>(EncodedMessage<FidlType> msg);
-
-  friend EncodeResult<FidlType> Encode<FidlType>(DecodedMessage<FidlType> msg);
-
-  // Use the FIDL encoding tables for |FidlType| to walk the message and
-  // destroy the handles it contains.
-  void CloseHandles() {
-    // Non-resource types do not contain handles, hence need no handle closing.
-    if constexpr (!FidlType::IsResource) {
-      return;
-    }
-#ifdef __Fuchsia__
-    if (bytes_.data()) {
-      fidl_close_handles(FidlType::Type, bytes_.data(), nullptr);
-    }
-#endif
-  }
-
-  // The contents of the decoded message.
-  BytePart bytes_;
-};
-
-}  // namespace fidl
-
-#endif  // LIB_FIDL_LLCPP_DECODED_MESSAGE_H_
diff --git a/zircon/system/ulib/fidl/include/lib/fidl/llcpp/encoded_message.h b/zircon/system/ulib/fidl/include/lib/fidl/llcpp/encoded_message.h
deleted file mode 100644
index 8a4311b..0000000
--- a/zircon/system/ulib/fidl/include/lib/fidl/llcpp/encoded_message.h
+++ /dev/null
@@ -1,205 +0,0 @@
-// Copyright 2018 The Fuchsia Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-#ifndef LIB_FIDL_LLCPP_ENCODED_MESSAGE_H_
-#define LIB_FIDL_LLCPP_ENCODED_MESSAGE_H_
-
-#include <lib/fidl/cpp/message.h>
-#include <lib/fidl/cpp/message_part.h>
-#include <lib/fidl/internal_callable_traits.h>
-#include <lib/fidl/llcpp/traits.h>
-#include <zircon/assert.h>
-#include <zircon/fidl.h>
-
-#include <algorithm>
-#include <cstdint>
-#include <iterator>
-#include <type_traits>
-#include <utility>
-
-#ifdef __Fuchsia__
-#include <lib/zx/channel.h>
-#include <zircon/syscalls.h>
-#endif
-
-namespace fidl {
-
-namespace internal {
-
-// When |NumHandles| is zero, |handle_storage| is always NULL.
-// This way we avoid declaring a C array with zero number of elements.
-template <uint32_t MaxNumHandles, typename Enabled = void>
-class EncodedMessageHandleHolder;
-
-template <uint32_t MaxNumHandles>
-class EncodedMessageHandleHolder<MaxNumHandles, std::enable_if_t<(MaxNumHandles > 0)>> {
- protected:
-  constexpr static uint32_t kResolvedMaxHandles =
-      MaxNumHandles > ZX_CHANNEL_MAX_MSG_HANDLES ? ZX_CHANNEL_MAX_MSG_HANDLES : MaxNumHandles;
-
-  zx_handle_t* handle_storage() { return &handle_storage_[0]; }
-
- private:
-  zx_handle_t handle_storage_[kResolvedMaxHandles];
-};
-
-template <uint32_t MaxNumHandles>
-class EncodedMessageHandleHolder<MaxNumHandles, std::enable_if_t<(MaxNumHandles == 0)>> {
- protected:
-  constexpr static uint32_t kResolvedMaxHandles = 0;
-
-  zx_handle_t* handle_storage() { return nullptr; }
-};
-
-}  // namespace internal
-
-class RawMessage {
- public:
-  RawMessage(BytePart bytes, HandlePart handles)
-      : bytes_(std::move(bytes)), handles_(std::move(handles)) {}
-  explicit RawMessage(HandlePart handles) : handles_(std::move(handles)) {}
-
-  BytePart& bytes() { return bytes_; }
-  const BytePart& bytes() const { return bytes_; }
-
-  HandlePart& handles() { return handles_; }
-  const HandlePart& handles() const { return handles_; }
-
- private:
-  BytePart bytes_;
-  HandlePart handles_;
-};
-
-// Holds an encoded FIDL message, that is, a byte array plus a handle table.
-//
-// The bytes part points to an external caller-managed buffer, while the handles part
-// is owned by this class. Any handles will be closed upon destruction.
-// This class is aware of the upper bound on the number of handles
-// in a message, such that its size can be adjusted to fit the demands
-// of a specific FIDL type.
-//
-// Because this class does not own the underlying message buffer, the caller
-// must make sure the lifetime of this class does not extend over that of the buffer.
-//
-// TODO(fxbug.dev/8093): Right now we assume EncodedMessage is always used in a |kReceiving|
-// context, which over-allocates bytes and handles for flexible messages. To be more frugal with
-// allocation, we should plumb the context through EncodedMessage.
-template <typename FidlType>
-class EncodedMessage final
-    : public internal::EncodedMessageHandleHolder<
-          internal::ClampedHandleCount<FidlType, MessageDirection::kReceiving>()> {
-  static_assert(IsFidlType<FidlType>::value, "Only FIDL types allowed here");
-  static_assert(FidlType::PrimarySize > 0, "Positive message size");
-
-  using Super = internal::EncodedMessageHandleHolder<
-      internal::ClampedHandleCount<FidlType, MessageDirection::kReceiving>()>;
-
- public:
-  // The maximum number of handles allowed in a message of this type, given the constraints
-  // of a zircon channel packet.
-  constexpr static uint32_t kResolvedMaxHandles = Super::kResolvedMaxHandles;
-
-  // Instantiates an empty buffer with no bytes or handles.
-  EncodedMessage() : message_(HandlePart(Super::handle_storage(), kResolvedMaxHandles)) {}
-
-  // Construct an |EncodedMessage| borrowing the bytes and taking ownership of handles in |msg|.
-  // The number of handles in |msg| must not exceed |kResolvedMaxHandles|.
-  explicit EncodedMessage(fidl_incoming_msg_t* msg)
-      : message_(BytePart(static_cast<uint8_t*>(msg->bytes), msg->num_bytes, msg->num_bytes),
-                 HandlePart(Super::handle_storage(), kResolvedMaxHandles)) {
-    ZX_ASSERT(msg->num_handles <= kResolvedMaxHandles);
-    if (kResolvedMaxHandles > 0) {
-      memcpy(handles().data(), msg->handles, sizeof(zx_handle_t) * msg->num_handles);
-      for (uint32_t i = 0; i < msg->num_handles; i++) {
-        msg->handles[i] = ZX_HANDLE_INVALID;
-      }
-      handles().set_actual(msg->num_handles);
-    } else {
-      handles().set_actual(0);
-    }
-  }
-
-  EncodedMessage(EncodedMessage&& other) noexcept
-      : message_(HandlePart(Super::handle_storage(), kResolvedMaxHandles)) {
-    if (this != &other) {
-      MoveImpl(std::move(other));
-    }
-  }
-
-  EncodedMessage& operator=(EncodedMessage&& other) noexcept {
-    if (this != &other) {
-      MoveImpl(std::move(other));
-    }
-    return *this;
-  }
-
-  EncodedMessage(const EncodedMessage& other) = delete;
-
-  EncodedMessage& operator=(const EncodedMessage& other) = delete;
-
-  // Instantiates an EncodedMessage which points to a buffer region with caller-managed memory.
-  // It does not take ownership of that buffer region.
-  // Also initializes an empty handles part.
-  explicit EncodedMessage(BytePart bytes)
-      : message_(std::move(bytes), HandlePart(Super::handle_storage(), kResolvedMaxHandles)) {}
-
-  ~EncodedMessage() { CloseHandles(); }
-
-  // Takes ownership of the contents of the message.
-  // The bytes and handle parts will become empty, while the existing bytes part is returned.
-  // The caller is responsible for having transferred the handles elsewhere
-  // before calling this method.
-  BytePart ReleaseBytesAndHandles() {
-    handles().set_actual(0);
-    return std::move(bytes());
-  }
-
-  const BytePart& bytes() const { return message_.bytes(); }
-  BytePart& bytes() { return message_.bytes(); }
-
-  const HandlePart& handles() const { return message_.handles(); }
-  HandlePart& handles() { return message_.handles(); }
-
-  // Take ownership of bytes and handles and assemble into a |fidl::Message|.
-  Message ToAnyMessage() { return Message(std::move(bytes()), std::move(handles())); }
-
- private:
-  void CloseHandles() {
-    if (kResolvedMaxHandles == 0) {
-      return;
-    }
-    if (handles().actual() > 0) {
-#ifdef __Fuchsia__
-      ZX_DEBUG_ASSERT(handles().actual() <= kResolvedMaxHandles);
-      zx_handle_close_many(handles().data(), handles().actual());
-#else
-      // How did we have handles if not on Fuchsia? Something bad happened...
-      assert(false);
-#endif
-      handles().set_actual(0);
-    }
-  }
-
-  void MoveImpl(EncodedMessage&& other) noexcept {
-    CloseHandles();
-    bytes() = std::move(other.bytes());
-#ifdef __Fuchsia__
-    ZX_DEBUG_ASSERT(other.handles().actual() <= kResolvedMaxHandles);
-#endif
-    if (kResolvedMaxHandles > 0) {
-      // copy handles from |other|
-      memcpy(Super::handle_storage(), other.Super::handle_storage(),
-             other.handles().actual() * sizeof(zx_handle_t));
-    }
-    // release handles in |other|
-    handles().set_actual(other.handles().actual());
-    other.handles().set_actual(0);
-  }
-
-  RawMessage message_;
-};
-
-}  // namespace fidl
-
-#endif  // LIB_FIDL_LLCPP_ENCODED_MESSAGE_H_
diff --git a/zircon/system/ulib/fidl/include/lib/fidl/llcpp/sync_call.h b/zircon/system/ulib/fidl/include/lib/fidl/llcpp/sync_call.h
index 9cf536b..7ce5f34 100644
--- a/zircon/system/ulib/fidl/include/lib/fidl/llcpp/sync_call.h
+++ b/zircon/system/ulib/fidl/include/lib/fidl/llcpp/sync_call.h
@@ -6,8 +6,6 @@
 #define LIB_FIDL_LLCPP_SYNC_CALL_H_
 
 #include <lib/fidl/llcpp/coding.h>
-#include <lib/fidl/llcpp/decoded_message.h>
-#include <lib/fidl/llcpp/encoded_message.h>
 #include <lib/fidl/llcpp/message_storage.h>
 #include <lib/fidl/llcpp/traits.h>
 
diff --git a/zircon/system/ulib/fidl/include/lib/fidl/llcpp/transaction.h b/zircon/system/ulib/fidl/include/lib/fidl/llcpp/transaction.h
index cd7384c..456663c 100644
--- a/zircon/system/ulib/fidl/include/lib/fidl/llcpp/transaction.h
+++ b/zircon/system/ulib/fidl/include/lib/fidl/llcpp/transaction.h
@@ -6,8 +6,6 @@
 #define LIB_FIDL_LLCPP_TRANSACTION_H_
 
 #include <lib/fidl/cpp/message.h>
-#include <lib/fidl/llcpp/decoded_message.h>
-#include <lib/fidl/llcpp/encoded_message.h>
 #include <lib/fidl/llcpp/message_storage.h>
 #include <lib/fidl/llcpp/result.h>
 #include <lib/fidl/llcpp/traits.h>