diff --git a/codegen/data.go b/codegen/data.go
index ef92ec8b48f..d3b191f8f94 100644
--- a/codegen/data.go
+++ b/codegen/data.go
@@ -6,9 +6,11 @@ import (
 	"sort"
 
 	"github.com/99designs/gqlgen/codegen/config"
+	"github.com/99designs/gqlgen/internal/code"
 	"github.com/pkg/errors"
 	"github.com/vektah/gqlparser/ast"
 	"github.com/vektah/gqlparser/formatter"
+	"golang.org/x/tools/go/packages"
 )
 
 // Data is a unified model of the code to be generated. Plugins may modify this structure to do things like implement
@@ -88,6 +90,12 @@ func BuildData(cfg *config.Config, plugins []SchemaMutator) (*Data, error) {
 		}
 	}
 
+	pkgs, err := packages.Load(&packages.Config{Mode: packages.NeedName}, cfg.Models.ReferencedPackages()...)
+	if err != nil {
+		return nil, errors.Wrap(err, "loading failed")
+	}
+	code.RecordPackagesList(pkgs)
+
 	s := Data{
 		Config:     cfg,
 		Directives: dataDirectives,
diff --git a/codegen/templates/import_test.go b/codegen/templates/import_test.go
index d225457576f..440b59147c5 100644
--- a/codegen/templates/import_test.go
+++ b/codegen/templates/import_test.go
@@ -5,7 +5,9 @@ import (
 	"os"
 	"testing"
 
+	"github.com/99designs/gqlgen/internal/code"
 	"github.com/stretchr/testify/require"
+	"golang.org/x/tools/go/packages"
 )
 
 func TestImports(t *testing.T) {
@@ -16,6 +18,11 @@ func TestImports(t *testing.T) {
 	bBar := "github.com/99designs/gqlgen/codegen/templates/testdata/b/bar"
 	mismatch := "github.com/99designs/gqlgen/codegen/templates/testdata/pkg_mismatch"
 
+	ps, err := packages.Load(nil, aBar, bBar, mismatch)
+	require.NoError(t, err)
+
+	code.RecordPackagesList(ps)
+
 	t.Run("multiple lookups is ok", func(t *testing.T) {
 		a := Imports{destDir: wd}
 
diff --git a/internal/code/imports.go b/internal/code/imports.go
index 3660079633a..10b325ba6f1 100644
--- a/internal/code/imports.go
+++ b/internal/code/imports.go
@@ -2,6 +2,7 @@ package code
 
 import (
 	"errors"
+	"fmt"
 	"go/build"
 	"go/parser"
 	"go/token"
@@ -14,7 +15,8 @@ import (
 	"golang.org/x/tools/go/packages"
 )
 
-var nameForPackageCache = sync.Map{}
+var nameForPackageCacheLock sync.Mutex
+var nameForPackageCache []*packages.Package
 
 var gopaths []string
 
@@ -107,24 +109,32 @@ func ImportPathForDir(dir string) (res string) {
 
 var modregex = regexp.MustCompile("module (.*)\n")
 
+// RecordPackagesList records the list of packages to be used later by NameForPackage.
+// It must be called exactly once during initialization, before NameForPackage is called.
+func RecordPackagesList(newNameForPackageCache []*packages.Package) {
+	nameForPackageCache = newNameForPackageCache
+}
+
 // NameForPackage returns the package name for a given import path. This can be really slow.
 func NameForPackage(importPath string) string {
 	if importPath == "" {
 		panic(errors.New("import path can not be empty"))
 	}
-	if v, ok := nameForPackageCache.Load(importPath); ok {
-		return v.(string)
+	if nameForPackageCache == nil {
+		panic(fmt.Errorf("NameForPackage called for %s before RecordPackagesList", importPath))
+	}
+	nameForPackageCacheLock.Lock()
+	defer nameForPackageCacheLock.Unlock()
+	var p *packages.Package
+	for _, pkg := range nameForPackageCache {
+		if pkg.PkgPath == importPath {
+			p = pkg
+			break
+		}
 	}
-	importPath = QualifyPackagePath(importPath)
-	p, _ := packages.Load(&packages.Config{
-		Mode: packages.NeedName,
-	}, importPath)
 
-	if len(p) != 1 || p[0].Name == "" {
+	if p == nil || p.Name == "" {
 		return SanitizePackageName(filepath.Base(importPath))
 	}
-
-	nameForPackageCache.Store(importPath, p[0].Name)
-
-	return p[0].Name
+	return p.Name
 }
diff --git a/internal/code/imports_test.go b/internal/code/imports_test.go
index e3bc9474f99..f7e6f24a5a5 100644
--- a/internal/code/imports_test.go
+++ b/internal/code/imports_test.go
@@ -8,6 +8,7 @@ import (
 
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
+	"golang.org/x/tools/go/packages"
 )
 
 func TestImportPathForDir(t *testing.T) {
@@ -31,11 +32,17 @@ func TestImportPathForDir(t *testing.T) {
 }
 
 func TestNameForPackage(t *testing.T) {
-	assert.Equal(t, "api", NameForPackage("github.com/99designs/gqlgen/api"))
+	testPkg1 := "github.com/99designs/gqlgen/api"
+	testPkg2 := "github.com/99designs/gqlgen/docs"
+	testPkg3 := "github.com"
+	ps, err := packages.Load(nil, testPkg1, testPkg2, testPkg3)
+	require.NoError(t, err)
+	RecordPackagesList(ps)
+	assert.Equal(t, "api", NameForPackage(testPkg1))
 
 	// does not contain go code, should still give a valid name
-	assert.Equal(t, "docs", NameForPackage("github.com/99designs/gqlgen/docs"))
-	assert.Equal(t, "github_com", NameForPackage("github.com"))
+	assert.Equal(t, "docs", NameForPackage(testPkg2))
+	assert.Equal(t, "github_com", NameForPackage(testPkg3))
 }
 
 func TestNameForDir(t *testing.T) {
diff --git a/internal/imports/prune_test.go b/internal/imports/prune_test.go
index d0691bf242e..5f1563e510b 100644
--- a/internal/imports/prune_test.go
+++ b/internal/imports/prune_test.go
@@ -4,10 +4,15 @@ import (
 	"io/ioutil"
 	"testing"
 
+	"github.com/99designs/gqlgen/internal/code"
 	"github.com/stretchr/testify/require"
+	"golang.org/x/tools/go/packages"
 )
 
 func TestPrune(t *testing.T) {
+	// prime the packages cache so that it's not considered uninitialized
+	code.RecordPackagesList([]*packages.Package{})
+
 	b, err := Prune("testdata/unused.go", mustReadFile("testdata/unused.go"))
 	require.NoError(t, err)
 	require.Equal(t, string(mustReadFile("testdata/unused.expected.go")), string(b))
diff --git a/plugin/modelgen/models.go b/plugin/modelgen/models.go
index 3458b42bdf5..8e976c65bf1 100644
--- a/plugin/modelgen/models.go
+++ b/plugin/modelgen/models.go
@@ -7,8 +7,11 @@ import (
 
 	"github.com/99designs/gqlgen/codegen/config"
 	"github.com/99designs/gqlgen/codegen/templates"
+	"github.com/99designs/gqlgen/internal/code"
 	"github.com/99designs/gqlgen/plugin"
+	"github.com/pkg/errors"
 	"github.com/vektah/gqlparser/ast"
+	"golang.org/x/tools/go/packages"
 )
 
 type BuildMutateHook = func(b *ModelBuild) *ModelBuild
@@ -246,6 +249,12 @@ func (m *Plugin) MutateConfig(cfg *config.Config) error {
 		b = m.MutateHook(b)
 	}
 
+	pkgs, err := packages.Load(&packages.Config{Mode: packages.NeedName}, cfg.Models.ReferencedPackages()...)
+	if err != nil {
+		return errors.Wrap(err, "loading failed")
+	}
+	code.RecordPackagesList(pkgs)
+
 	return templates.Render(templates.Options{
 		PackageName:     cfg.Model.Package,
 		Filename:        cfg.Model.Filename,