diff --git a/include/swift/AST/Attr.def b/include/swift/AST/Attr.def
index 4f40cdc2b04bc..e9b72bb7c55b6 100644
--- a/include/swift/AST/Attr.def
+++ b/include/swift/AST/Attr.def
@@ -52,6 +52,7 @@ TYPE_ATTR(convention)
 TYPE_ATTR(noescape)
 TYPE_ATTR(escaping)
 TYPE_ATTR(differentiable)
+TYPE_ATTR(noDerivative)
 
 // SIL-specific attributes
 TYPE_ATTR(block_storage)
diff --git a/include/swift/AST/DiagnosticsSema.def b/include/swift/AST/DiagnosticsSema.def
index 36b0e01566ac8..829b4821b5a97 100644
--- a/include/swift/AST/DiagnosticsSema.def
+++ b/include/swift/AST/DiagnosticsSema.def
@@ -3926,6 +3926,11 @@ ERROR(opaque_type_in_protocol_requirement,none,
       "'some' type cannot be the return type of a protocol requirement; did you mean to add an associated type?",
       ())
 
+// Function differentiability
+ERROR(attr_only_on_parameters_of_differentiable,none,
+      "'%0' may only be used on parameters of '@differentiable' function "
+      "types", (StringRef))
+
 // SIL
 ERROR(opened_non_protocol,none,
       "@opened cannot be applied to non-protocol type %0", (Type))
diff --git a/include/swift/AST/Types.h b/include/swift/AST/Types.h
index 8943ea372446b..c03a523d0ae40 100644
--- a/include/swift/AST/Types.h
+++ b/include/swift/AST/Types.h
@@ -1808,8 +1808,8 @@ class ParameterTypeFlags {
     NonEphemeral = 1 << 2,
     OwnershipShift = 3,
     Ownership    = 7 << OwnershipShift,
-
-    NumBits = 6
+    NoDerivative = 1 << 7,
+    NumBits = 7
   };
   OptionSet<ParameterFlags> value;
   static_assert(NumBits < 8*sizeof(OptionSet<ParameterFlags>), "overflowed");
@@ -1823,15 +1823,17 @@ class ParameterTypeFlags {
   }
 
   ParameterTypeFlags(bool variadic, bool autoclosure, bool nonEphemeral,
-                     ValueOwnership ownership)
+                     ValueOwnership ownership, bool noDerivative)
       : value((variadic ? Variadic : 0) | (autoclosure ? AutoClosure : 0) |
               (nonEphemeral ? NonEphemeral : 0) |
-              uint8_t(ownership) << OwnershipShift) {}
+              uint8_t(ownership) << OwnershipShift |
+              (noDerivative ? NoDerivative : 0)) {}
 
   /// Create one from what's present in the parameter type
   inline static ParameterTypeFlags
   fromParameterType(Type paramTy, bool isVariadic, bool isAutoClosure,
-                    bool isNonEphemeral, ValueOwnership ownership);
+                    bool isNonEphemeral, ValueOwnership ownership,
+                    bool isNoDerivative);
 
   bool isNone() const { return !value; }
   bool isVariadic() const { return value.contains(Variadic); }
@@ -1840,6 +1842,7 @@ class ParameterTypeFlags {
   bool isInOut() const { return getValueOwnership() == ValueOwnership::InOut; }
   bool isShared() const { return getValueOwnership() == ValueOwnership::Shared;}
   bool isOwned() const { return getValueOwnership() == ValueOwnership::Owned; }
+  bool isNoDerivative() const { return value.contains(NoDerivative); }
 
   ValueOwnership getValueOwnership() const {
     return ValueOwnership((value.toRaw() & Ownership) >> OwnershipShift);
@@ -1882,6 +1885,12 @@ class ParameterTypeFlags {
                                   : value - ParameterTypeFlags::NonEphemeral);
   }
 
+  ParameterTypeFlags withNoDerivative(bool noDerivative) const {
+    return ParameterTypeFlags(noDerivative
+                                  ? value | ParameterTypeFlags::NoDerivative
+                                  : value - ParameterTypeFlags::NoDerivative);
+  }
+
   bool operator ==(const ParameterTypeFlags &other) const {
     return value.toRaw() == other.value.toRaw();
   }
@@ -1948,8 +1957,8 @@ class YieldTypeFlags {
   ParameterTypeFlags asParamFlags() const {
     return ParameterTypeFlags(/*variadic*/ false,
                               /*autoclosure*/ false,
-                              /*nonEphemeral*/ false,
-                              getValueOwnership());
+                              /*nonEphemeral*/ false, getValueOwnership(),
+                              /*noDerivative*/ false);
   }
 
   bool operator ==(const YieldTypeFlags &other) const {
@@ -2821,6 +2830,9 @@ class AnyFunctionType : public TypeBase {
     /// Whether the parameter is marked '@_nonEphemeral'
     bool isNonEphemeral() const { return Flags.isNonEphemeral(); }
 
+    /// Whether the parameter is marked '@noDerivative'.
+    bool isNoDerivative() const { return Flags.isNoDerivative(); }
+
     ValueOwnership getValueOwnership() const {
       return Flags.getValueOwnership();
     }
@@ -5818,10 +5830,9 @@ inline TupleTypeElt TupleTypeElt::getWithType(Type T) const {
 }
 
 /// Create one from what's present in the parameter decl and type
-inline ParameterTypeFlags
-ParameterTypeFlags::fromParameterType(Type paramTy, bool isVariadic,
-                                      bool isAutoClosure, bool isNonEphemeral,
-                                      ValueOwnership ownership) {
+inline ParameterTypeFlags ParameterTypeFlags::fromParameterType(
+    Type paramTy, bool isVariadic, bool isAutoClosure, bool isNonEphemeral,
+    ValueOwnership ownership, bool isNoDerivative) {
   // FIXME(Remove InOut): The last caller that needs this is argument
   // decomposition.  Start by enabling the assertion there and fixing up those
   // callers, then remove this, then remove
@@ -5831,7 +5842,7 @@ ParameterTypeFlags::fromParameterType(Type paramTy, bool isVariadic,
            ownership == ValueOwnership::InOut);
     ownership = ValueOwnership::InOut;
   }
-  return {isVariadic, isAutoClosure, isNonEphemeral, ownership};
+  return {isVariadic, isAutoClosure, isNonEphemeral, ownership, isNoDerivative};
 }
 
 inline const Type *BoundGenericType::getTrailingObjectsPointer() const {
diff --git a/lib/AST/ASTContext.cpp b/lib/AST/ASTContext.cpp
index 805f472be89d4..db8035eadacb0 100644
--- a/lib/AST/ASTContext.cpp
+++ b/lib/AST/ASTContext.cpp
@@ -2893,9 +2893,10 @@ void AnyFunctionType::decomposeInput(
   }
       
   default:
-    result.emplace_back(type->getInOutObjectType(), Identifier(),
-                        ParameterTypeFlags::fromParameterType(
-                          type, false, false, false, ValueOwnership::Default));
+    result.emplace_back(
+        type->getInOutObjectType(), Identifier(),
+        ParameterTypeFlags::fromParameterType(type, false, false, false,
+                                              ValueOwnership::Default, false));
     return;
   }
 }
diff --git a/lib/AST/ASTPrinter.cpp b/lib/AST/ASTPrinter.cpp
index e0212538f1261..e4e038947fc01 100644
--- a/lib/AST/ASTPrinter.cpp
+++ b/lib/AST/ASTPrinter.cpp
@@ -2502,6 +2502,8 @@ static void printParameterFlags(ASTPrinter &printer, PrintOptions options,
                                 ParameterTypeFlags flags, bool escaping) {
   if (!options.excludeAttrKind(TAK_autoclosure) && flags.isAutoClosure())
     printer << "@autoclosure ";
+  if (!options.excludeAttrKind(TAK_noDerivative) && flags.isNoDerivative())
+    printer << "@noDerivative ";
 
   switch (flags.getValueOwnership()) {
   case ValueOwnership::Default:
diff --git a/lib/AST/Decl.cpp b/lib/AST/Decl.cpp
index 5cf8d55f85146..64abf260a60ba 100644
--- a/lib/AST/Decl.cpp
+++ b/lib/AST/Decl.cpp
@@ -6039,11 +6039,10 @@ AnyFunctionType::Param ParamDecl::toFunctionParam(Type type) const {
     type = ParamDecl::getVarargBaseTy(type);
 
   auto label = getArgumentName();
-  auto flags = ParameterTypeFlags::fromParameterType(type,
-                                                     isVariadic(),
-                                                     isAutoClosure(),
-                                                     isNonEphemeral(),
-                                                     getValueOwnership());
+  auto flags = ParameterTypeFlags::fromParameterType(
+      type, isVariadic(), isAutoClosure(), isNonEphemeral(),
+      getValueOwnership(),
+      /*isNoDerivative*/ false);
   return AnyFunctionType::Param(type, label, flags);
 }
 
diff --git a/lib/AST/TypeRepr.cpp b/lib/AST/TypeRepr.cpp
index 200f3aa5604e4..7340027e31c8d 100644
--- a/lib/AST/TypeRepr.cpp
+++ b/lib/AST/TypeRepr.cpp
@@ -298,6 +298,8 @@ void AttributedTypeRepr::printAttrs(ASTPrinter &Printer,
     Printer.printSimpleAttr("@autoclosure") << " ";
   if (hasAttr(TAK_escaping))
     Printer.printSimpleAttr("@escaping") << " ";
+  if (hasAttr(TAK_noDerivative))
+    Printer.printSimpleAttr("@noDerivative") << " ";
 
   if (hasAttr(TAK_differentiable)) {
     if (Attrs.isLinear()) {
diff --git a/lib/Sema/TypeCheckType.cpp b/lib/Sema/TypeCheckType.cpp
index c3616371deeec..3158e3be8ef1c 100644
--- a/lib/Sema/TypeCheckType.cpp
+++ b/lib/Sema/TypeCheckType.cpp
@@ -1793,6 +1793,7 @@ namespace {
     resolveASTFunctionTypeParams(TupleTypeRepr *inputRepr,
                                  TypeResolutionOptions options,
                                  bool requiresMappingOut,
+                                 DifferentiabilityKind diffKind,
                                  SmallVectorImpl<AnyFunctionType::Param> &ps);
 
     Type resolveSILFunctionType(FunctionTypeRepr *repr,
@@ -2026,6 +2027,11 @@ Type TypeResolver::resolveAttributedType(TypeAttributes &attrs,
   // Remember whether this is a function parameter.
   bool isParam = options.is(TypeResolverContext::FunctionInput);
 
+  // Remember whether this is a variadic function parameter.
+  bool isVariadicFunctionParam =
+      options.is(TypeResolverContext::VariadicFunctionInput) &&
+      !options.hasBase(TypeResolverContext::EnumElementDecl);
+
   // The type we're working with, in case we want to build it differently
   // based on the attributes we see.
   Type ty;
@@ -2370,6 +2376,21 @@ Type TypeResolver::resolveAttributedType(TypeAttributes &attrs,
     attrs.ConventionArguments = None;
   }
 
+  if (attrs.has(TAK_noDerivative)) {
+    if (!Context.LangOpts.EnableExperimentalDifferentiableProgramming) {
+      diagnose(attrs.getLoc(TAK_noDerivative),
+               diag::experimental_differentiable_programming_disabled);
+    } else if (!isParam) {
+      // @noDerivative is only valid on parameters.
+      diagnose(attrs.getLoc(TAK_noDerivative),
+               (isVariadicFunctionParam
+                    ? diag::attr_not_on_variadic_parameters
+                    : diag::attr_only_on_parameters_of_differentiable),
+               "@noDerivative");
+    }
+    attrs.clearAttribute(TAK_noDerivative);
+  }
+
   // In SIL, handle @opened (n), which creates an existential archetype.
   if (attrs.has(TAK_opened)) {
     if (!ty->isExistentialType()) {
@@ -2422,7 +2443,7 @@ Type TypeResolver::resolveAttributedType(TypeAttributes &attrs,
 
 bool TypeResolver::resolveASTFunctionTypeParams(
     TupleTypeRepr *inputRepr, TypeResolutionOptions options,
-    bool requiresMappingOut,
+    bool requiresMappingOut, DifferentiabilityKind diffKind,
     SmallVectorImpl<AnyFunctionType::Param> &elements) {
   elements.reserve(inputRepr->getNumElements());
 
@@ -2486,8 +2507,24 @@ bool TypeResolver::resolveASTFunctionTypeParams(
       ownership = ValueOwnership::Default;
       break;
     }
+
+    bool noDerivative = false;
+    if (auto *attrTypeRepr = dyn_cast<AttributedTypeRepr>(eltTypeRepr)) {
+      if (attrTypeRepr->getAttrs().has(TAK_noDerivative)) {
+        if (diffKind == DifferentiabilityKind::NonDifferentiable &&
+            Context.LangOpts.EnableExperimentalDifferentiableProgramming)
+          diagnose(eltTypeRepr->getLoc(),
+                   diag::attr_only_on_parameters_of_differentiable,
+                   "@noDerivative")
+              .highlight(eltTypeRepr->getSourceRange());
+        else
+          noDerivative = true;
+      }
+    }
+
     auto paramFlags = ParameterTypeFlags::fromParameterType(
-        ty, variadic, autoclosure, /*isNonEphemeral*/ false, ownership);
+        ty, variadic, autoclosure, /*isNonEphemeral*/ false, ownership,
+        noDerivative);
     elements.emplace_back(ty, Identifier(), paramFlags);
   }
 
@@ -2541,7 +2578,8 @@ Type TypeResolver::resolveASTFunctionType(
 
   SmallVector<AnyFunctionType::Param, 8> params;
   if (resolveASTFunctionTypeParams(repr->getArgsTypeRepr(), options,
-                         repr->getGenericEnvironment() != nullptr, params)) {
+                                   repr->getGenericEnvironment() != nullptr,
+                                   diffKind, params)) {
     return Type();
   }
 
diff --git a/lib/Serialization/Deserialization.cpp b/lib/Serialization/Deserialization.cpp
index 31646a5219c2a..f260a588bec93 100644
--- a/lib/Serialization/Deserialization.cpp
+++ b/lib/Serialization/Deserialization.cpp
@@ -4770,12 +4770,11 @@ class swift::TypeDeserializer {
 
       IdentifierID labelID;
       TypeID typeID;
-      bool isVariadic, isAutoClosure, isNonEphemeral;
+      bool isVariadic, isAutoClosure, isNonEphemeral, isNoDerivative;
       unsigned rawOwnership;
-      decls_block::FunctionParamLayout::readRecord(scratch, labelID, typeID,
-                                                   isVariadic, isAutoClosure,
-                                                   isNonEphemeral,
-                                                   rawOwnership);
+      decls_block::FunctionParamLayout::readRecord(
+          scratch, labelID, typeID, isVariadic, isAutoClosure, isNonEphemeral,
+          rawOwnership, isNoDerivative);
 
       auto ownership =
           getActualValueOwnership((serialization::ValueOwnership)rawOwnership);
@@ -4786,10 +4785,10 @@ class swift::TypeDeserializer {
       if (!paramTy)
         return paramTy.takeError();
 
-      params.emplace_back(paramTy.get(),
-                          MF.getIdentifier(labelID),
+      params.emplace_back(paramTy.get(), MF.getIdentifier(labelID),
                           ParameterTypeFlags(isVariadic, isAutoClosure,
-                                             isNonEphemeral, *ownership));
+                                             isNonEphemeral, *ownership,
+                                             isNoDerivative));
     }
 
     if (!isGeneric) {
diff --git a/lib/Serialization/ModuleFormat.h b/lib/Serialization/ModuleFormat.h
index 284004efed076..b1c96011230b7 100644
--- a/lib/Serialization/ModuleFormat.h
+++ b/lib/Serialization/ModuleFormat.h
@@ -55,7 +55,7 @@ const uint16_t SWIFTMODULE_VERSION_MAJOR = 0;
 /// describe what change you made. The content of this comment isn't important;
 /// it just ensures a conflict if two people change the module format.
 /// Don't worry about adhering to the 80-column limit for this line.
-const uint16_t SWIFTMODULE_VERSION_MINOR = 530; // @_implicitly_synthesizes_nested_requirement
+const uint16_t SWIFTMODULE_VERSION_MINOR = 531; // function parameter noDerivative
 
 /// A standard hash seed used for all string hashes in a serialized module.
 ///
@@ -905,12 +905,13 @@ namespace decls_block {
 
   using FunctionParamLayout = BCRecordLayout<
     FUNCTION_PARAM,
-    IdentifierIDField,  // name
-    TypeIDField,        // type
-    BCFixed<1>,         // vararg?
-    BCFixed<1>,         // autoclosure?
-    BCFixed<1>,         // non-ephemeral?
-    ValueOwnershipField // inout, shared or owned?
+    IdentifierIDField,   // name
+    TypeIDField,         // type
+    BCFixed<1>,          // vararg?
+    BCFixed<1>,          // autoclosure?
+    BCFixed<1>,          // non-ephemeral?
+    ValueOwnershipField, // inout, shared or owned?
+    BCFixed<1>           // noDerivative?
   >;
 
   using MetatypeTypeLayout = BCRecordLayout<
diff --git a/lib/Serialization/Serialization.cpp b/lib/Serialization/Serialization.cpp
index ba2ba44d2bc60..3f9471b7eb565 100644
--- a/lib/Serialization/Serialization.cpp
+++ b/lib/Serialization/Serialization.cpp
@@ -4021,8 +4021,8 @@ class Serializer::TypeSerializer : public TypeVisitor<TypeSerializer> {
           S.Out, S.ScratchRecord, abbrCode,
           S.addDeclBaseNameRef(param.getLabel()),
           S.addTypeRef(param.getPlainType()), paramFlags.isVariadic(),
-          paramFlags.isAutoClosure(), paramFlags.isNonEphemeral(),
-          rawOwnership);
+          paramFlags.isAutoClosure(), paramFlags.isNonEphemeral(), rawOwnership,
+          paramFlags.isNoDerivative());
     }
   }
 
diff --git a/test/AutoDiff/ModuleInterface/differentiation.swift b/test/AutoDiff/ModuleInterface/differentiation.swift
index 6b3a791fb9ca3..35ee0f9067891 100644
--- a/test/AutoDiff/ModuleInterface/differentiation.swift
+++ b/test/AutoDiff/ModuleInterface/differentiation.swift
@@ -6,3 +6,6 @@ public func a(f: @differentiable (Float) -> Float) {}
 
 public func b(f: @differentiable(linear) (Float) -> Float) {}
 // CHECK: public func b(f: @differentiable(linear) (Swift.Float) -> Swift.Float)
+
+public func c(f: @differentiable (Float, @noDerivative Float) -> Float) {}
+// CHECK: public func c(f: @differentiable (Swift.Float, @noDerivative Swift.Float) -> Swift.Float)
diff --git a/test/AutoDiff/Parse/differentiable_func_type.swift b/test/AutoDiff/Parse/differentiable_func_type.swift
index 7ef91d3524fb9..e163a246a4fba 100644
--- a/test/AutoDiff/Parse/differentiable_func_type.swift
+++ b/test/AutoDiff/Parse/differentiable_func_type.swift
@@ -8,12 +8,25 @@ let b: @differentiable(linear) (Float) -> Float // okay
 // CHECK: (pattern_named 'b'
 // CHECK-NEXT: (type_attributed attrs=@differentiable(linear)
 
-let c: @differentiable (Float) throws -> Float // okay
+let c: @differentiable (Float, @noDerivative Float) -> Float // okay
 // CHECK: (pattern_named 'c'
+// CHECK-NEXT: (type_attributed attrs=@differentiable
+// CHECK-NEXT:  (type_function
+// CHECK-NEXT:    (type_tuple
+// CHECK-NEXT:      (type_ident
+// CHECK-NEXT:        (component id='Float' bind=none))
+// CHECK-NEXT:      (type_attributed attrs=@noDerivative
+// CHECK-NEXT:        (type_ident
+// CHECK-NEXT:          (component id='Float' bind=none)))
+// CHECK-NEXT:    (type_ident
+// CHECK-NEXT:      (component id='Float' bind=none)))))
+
+let d: @differentiable (Float) throws -> Float // okay
+// CHECK: (pattern_named 'd'
 // CHECK-NEXT: (type_attributed attrs=@differentiable{{[^(]}}
 
-let d: @differentiable(linear) (Float) throws -> Float // okay
-// CHECK: (pattern_named 'd'
+let e: @differentiable(linear) (Float) throws -> Float // okay
+// CHECK: (pattern_named 'e'
 // CHECK-NEXT: (type_attributed attrs=@differentiable(linear)
 
 // Generic type test.
diff --git a/test/AutoDiff/Sema/differentiable_features_disabled.swift b/test/AutoDiff/Sema/differentiable_features_disabled.swift
index e8212a69258d8..1ba3ec05e8a80 100644
--- a/test/AutoDiff/Sema/differentiable_features_disabled.swift
+++ b/test/AutoDiff/Sema/differentiable_features_disabled.swift
@@ -3,6 +3,16 @@
 // expected-error @+1 {{differentiable programming is an experimental feature that is currently disabled}}
 let _: @differentiable (Float) -> Float
 
+// expected-error @+2 {{differentiable programming is an experimental feature that is currently disabled}}
+// expected-error @+1 {{differentiable programming is an experimental feature that is currently disabled}}
+let _: @differentiable (Float, @noDerivative Float) -> Float
+
+// expected-error @+1 {{differentiable programming is an experimental feature that is currently disabled}}
+let _: (Float, @noDerivative Float) -> Float
+
+// expected-error @+1 {{differentiable programming is an experimental feature that is currently disabled}}
+let _: @noDerivative Float
+
 func id(_ x: Float) -> Float {
   return x
 }
diff --git a/test/AutoDiff/Sema/differentiable_func_type.swift b/test/AutoDiff/Sema/differentiable_func_type.swift
index 0ca2f8aa50296..0515dcc95d027 100644
--- a/test/AutoDiff/Sema/differentiable_func_type.swift
+++ b/test/AutoDiff/Sema/differentiable_func_type.swift
@@ -4,3 +4,24 @@
 let _: @differentiable Float
 
 let _: @differentiable (Float) -> Float
+
+// expected-error @+1 {{'@noDerivative' may only be used on parameters of '@differentiable' function types}}
+let _: @noDerivative Float
+
+// expected-error @+1 {{'@noDerivative' may only be used on parameters of '@differentiable' function types}}
+let _: (Float) -> @noDerivative Float
+
+// expected-error @+1 {{'@noDerivative' may only be used on parameters of '@differentiable' function types}}
+let _: @differentiable (Float) -> @noDerivative Float
+
+// expected-error @+1 {{'@noDerivative' may only be used on parameters of '@differentiable' function types}}
+let _: (@noDerivative Float) -> Float
+
+// expected-error @+2 {{'@noDerivative' may only be used on parameters of '@differentiable' function types}}
+// expected-error @+1 {{'@noDerivative' must not be used on variadic parameters}}
+let _: (Float, @noDerivative Float...) -> Float
+
+let _: @differentiable (@noDerivative Float, Float) -> Float
+
+// expected-error @+1 {{'@noDerivative' must not be used on variadic parameters}}
+let _: @differentiable (Float, @noDerivative Float...) -> Float
diff --git a/test/AutoDiff/Serialization/differentiation.swift b/test/AutoDiff/Serialization/differentiation.swift
index d5f1276c3f494..3a17b5440b8a9 100644
--- a/test/AutoDiff/Serialization/differentiation.swift
+++ b/test/AutoDiff/Serialization/differentiation.swift
@@ -10,3 +10,6 @@ func a(_ f: @differentiable (Float) -> Float) {}
 
 func b(_ f: @differentiable(linear) (Float) -> Float) {}
 // CHECK: func b(_ f: @differentiable(linear) (Float) -> Float)
+
+func c(_ f: @differentiable (Float, @noDerivative Float) -> Float) {}
+// CHECK: func c(_ f: @differentiable (Float, @noDerivative Float) -> Float)