diff --git a/README.md b/README.md
index 0abf57f..71dbdb9 100644
--- a/README.md
+++ b/README.md
@@ -10,7 +10,7 @@ At the moment Kelpie is very much in development, and there are missing features
 
 The following is a list of known-outstanding features and known issues:
 
-- [ ] For some reason Kelpie is generating multiple mocks when specifying built-in interfaces. See the [Mock Generation](#mock-generation) section for an example.
+- [ ] Add support for embedded interfaces.
 
 ## Quickstart
 
@@ -96,7 +96,6 @@ Kelpie mock generation starting - preparing to add some magic to your code-base!
 
 Parsing package 'io' for interfaces to mock.
   - Generating a mock for 'Reader'.
-  - Generating a mock for 'Reader'.
 
 Parsing package 'github.com/adamconnelly/kelpie/examples' for interfaces to mock.
   - Generating a mock for 'Maths'.
diff --git a/examples/external_types_test.go b/examples/external_types_test.go
index 3446564..735eac7 100644
--- a/examples/external_types_test.go
+++ b/examples/external_types_test.go
@@ -3,9 +3,10 @@ package examples
 import (
 	"testing"
 
+	"github.com/stretchr/testify/suite"
+
 	"github.com/adamconnelly/kelpie"
 	"github.com/adamconnelly/kelpie/examples/mocks/reader"
-	"github.com/stretchr/testify/suite"
 )
 
 type ExternalTypesTests struct {
diff --git a/maps/maps.go b/maps/maps.go
index f3379ab..c31c3d5 100644
--- a/maps/maps.go
+++ b/maps/maps.go
@@ -12,3 +12,15 @@ func Keys[TKey comparable, TValue any](m map[TKey]TValue) []TKey {
 
 	return keys
 }
+
+// Values returns the values in the map.
+func Values[TKey comparable, TValue any](m map[TKey]TValue) []TValue {
+	values := make([]TValue, len(m))
+	index := 0
+	for _, v := range m {
+		values[index] = v
+		index++
+	}
+
+	return values
+}
diff --git a/parser/parser.go b/parser/parser.go
index 29a6727..536b11c 100644
--- a/parser/parser.go
+++ b/parser/parser.go
@@ -13,6 +13,7 @@ import (
 	"github.com/pkg/errors"
 	"golang.org/x/tools/go/packages"
 
+	"github.com/adamconnelly/kelpie/maps"
 	"github.com/adamconnelly/kelpie/slices"
 )
 
@@ -117,8 +118,6 @@ func (f *IncludingInterfaceFilter) Include(name string) bool {
 
 // Parse parses the source contained in the reader.
 func Parse(packageName string, directory string, filter InterfaceFilter) (*ParsedPackage, error) {
-	var interfaces []MockedInterface
-
 	pkgs, err := packages.Load(&packages.Config{
 		Mode:  packages.NeedName | packages.NeedTypes | packages.NeedImports | packages.NeedSyntax | packages.NeedTypesInfo | packages.NeedFiles,
 		Dir:   directory,
@@ -129,6 +128,7 @@ func Parse(packageName string, directory string, filter InterfaceFilter) (*Parse
 	}
 
 	var packageDirectory string
+	interfaces := map[string]MockedInterface{}
 
 	for _, p := range pkgs {
 		if len(p.Syntax) > 0 && len(p.GoFiles) > 0 {
@@ -144,11 +144,14 @@ func Parse(packageName string, directory string, filter InterfaceFilter) (*Parse
 					if t.Name.IsExported() {
 						if interfaceType, ok := t.Type.(*ast.InterfaceType); ok {
 							if filter.Include(t.Name.Name) {
-								interfaces = append(interfaces, parseInterface(t.Name.Name, t.Name.Name, interfaceType, p, fileNode.Imports))
+								i := parseInterface(t.Name.Name, t.Name.Name, interfaceType, p, fileNode.Imports)
+								interfaces[i.FullName] = i
 							}
 						} else if structType, ok := t.Type.(*ast.StructType); ok {
 							for _, f := range structType.Fields.List {
-								interfaces = append(interfaces, parseStructField(t, f, p, fileNode.Imports, filter)...)
+								for _, i := range parseStructField(t, f, p, fileNode.Imports, filter) {
+									interfaces[i.FullName] = i
+								}
 							}
 						}
 					}
@@ -164,7 +167,7 @@ func Parse(packageName string, directory string, filter InterfaceFilter) (*Parse
 		}
 	}
 
-	return &ParsedPackage{PackageDirectory: packageDirectory, Mocks: interfaces}, nil
+	return &ParsedPackage{PackageDirectory: packageDirectory, Mocks: maps.Values(interfaces)}, nil
 }
 
 func parseStructField(structNode *ast.TypeSpec, field *ast.Field, pkg *packages.Package, importSpecs []*ast.ImportSpec, filter InterfaceFilter) []MockedInterface {
diff --git a/parser/parser_test.go b/parser/parser_test.go
index e9ba9b8..e4c9d19 100644
--- a/parser/parser_test.go
+++ b/parser/parser_test.go
@@ -689,6 +689,21 @@ type DoubleNested struct {
 	t.Len(DoSomethingElse.Results, 2)
 }
 
+func (t *ParserTests) Test_Parse_CanParseStdlibInterfaces() {
+	// Arrange
+	t.interfaceFilter.Setup(interfacefilter.Include(kelpie.Any[string]()).Return(false))
+	t.interfaceFilter.Setup(interfacefilter.Include("Reader").Return(true))
+
+	// Act
+	result, err := parser.Parse("io", ".", t.interfaceFilter.Instance())
+
+	// Assert
+	t.NoError(err)
+	t.Len(result.Mocks, 1)
+	t.Len(result.Mocks[0].Methods, 1)
+	t.Equal("Read", result.Mocks[0].Methods[0].Name)
+}
+
 func (t *ParserTests) Test_MockedInterface_AnyMethodsHaveParameters_ReturnsFalseIfNoMethodsHaveParameters() {
 	// Arrange
 	mockedInterface := parser.MockedInterface{