diff --git a/cmd/dep/ensure.go b/cmd/dep/ensure.go
index 2190770836..ea07f0cd9d 100644
--- a/cmd/dep/ensure.go
+++ b/cmd/dep/ensure.go
@@ -52,6 +52,12 @@ dep ensure -update
     ignoring any versions specified in the lock file. Update the lock file with
     any changes.
 
+dep ensure -update github.com/pkg/foo github.com/pkg/bar
+
+    Update a list of dependencies to the latest versions allowed by the manifest,
+    ignoring any versions specified in the lock file. Update the lock file with
+    any changes.
+
 dep ensure github.com/pkg/foo@^1.0.1
 
     Constrain pkg/foo to the latest release matching >= 1.0.1, < 2.0.0, and
@@ -82,7 +88,7 @@ func (cmd *ensureCommand) Hidden() bool      { return false }
 
 func (cmd *ensureCommand) Register(fs *flag.FlagSet) {
 	fs.BoolVar(&cmd.examples, "examples", false, "print detailed usage examples")
-	fs.BoolVar(&cmd.update, "update", false, "ensure all dependencies are at the latest version allowed by the manifest")
+	fs.BoolVar(&cmd.update, "update", false, "ensure dependencies are at the latest version allowed by the manifest")
 	fs.BoolVar(&cmd.dryRun, "n", false, "dry run, don't actually ensure anything")
 	fs.Var(&cmd.overrides, "override", "specify an override constraint spec (repeatable)")
 }
@@ -100,10 +106,6 @@ func (cmd *ensureCommand) Run(ctx *dep.Ctx, args []string) error {
 		return nil
 	}
 
-	if cmd.update && len(args) > 0 {
-		return errors.New("Cannot pass -update and itemized project list (for now)")
-	}
-
 	p, err := ctx.LoadProject("")
 	if err != nil {
 		return err
@@ -116,9 +118,72 @@ func (cmd *ensureCommand) Run(ctx *dep.Ctx, args []string) error {
 	sm.UseDefaultSignalHandling()
 	defer sm.Release()
 
+	params := p.MakeParams()
+	if *verbose {
+		params.Trace = true
+		params.TraceLogger = log.New(os.Stderr, "", 0)
+	}
+	params.RootPackageTree, err = gps.ListPackages(p.AbsRoot, string(p.ImportRoot))
+	if err != nil {
+		return errors.Wrap(err, "ensure ListPackage for project")
+	}
+
+	if cmd.update {
+		applyUpdateArgs(args, &params)
+	} else {
+		err := applyEnsureArgs(args, cmd.overrides, p, sm, &params)
+		if err != nil {
+			return err
+		}
+	}
+
+	solver, err := gps.Prepare(params, sm)
+	if err != nil {
+		return errors.Wrap(err, "ensure Prepare")
+	}
+	solution, err := solver.Solve()
+	if err != nil {
+		handleAllTheFailuresOfTheWorld(err)
+		return errors.Wrap(err, "ensure Solve()")
+	}
+
+	sw := dep.SafeWriter{
+		Root:          p.AbsRoot,
+		Lock:          p.Lock,
+		NewLock:       solution,
+		SourceManager: sm,
+	}
+	if !cmd.update {
+		sw.Manifest = p.Manifest
+	}
+
+	// check if vendor exists, because if the locks are the same but
+	// vendor does not exist we should write vendor
+	vendorExists, err := dep.IsNonEmptyDir(filepath.Join(sw.Root, "vendor"))
+	if err != nil {
+		return errors.Wrap(err, "ensure vendor is a directory")
+	}
+	writeV := !vendorExists && solution != nil
+
+	return errors.Wrap(sw.WriteAllSafe(writeV), "grouped write of manifest, lock and vendor")
+}
+
+func applyUpdateArgs(args []string, params *gps.SolveParameters) {
+	// When -update is specified without args, allow every project to change versions, regardless of the lock file
+	if len(args) == 0 {
+		params.ChangeAll = true
+		return
+	}
+
+	// Allow any of specified project versions to change, regardless of the lock file
+	for _, arg := range args {
+		params.ToChange = append(params.ToChange, gps.ProjectRoot(arg))
+	}
+}
+
+func applyEnsureArgs(args []string, overrides stringSlice, p *dep.Project, sm *gps.SourceMgr, params *gps.SolveParameters) error {
 	var errs []error
 	for _, arg := range args {
-		// default persist to manifest
 		pc, err := getProjectConstraint(arg, sm)
 		if err != nil {
 			errs = append(errs, err)
@@ -144,18 +209,9 @@ func (cmd *ensureCommand) Run(ctx *dep.Ctx, args []string) error {
 			Source:     pc.Ident.Source,
 			Constraint: pc.Constraint,
 		}
-
-		if p.Lock != nil {
-			for i, lp := range p.Lock.P {
-				if lp.Ident() == pc.Ident {
-					p.Lock.P = append(p.Lock.P[:i], p.Lock.P[i+1:]...)
-					break
-				}
-			}
-		}
 	}
 
-	for _, ovr := range cmd.overrides {
+	for _, ovr := range overrides {
 		pc, err := getProjectConstraint(ovr, sm)
 		if err != nil {
 			errs = append(errs, err)
@@ -170,15 +226,6 @@ func (cmd *ensureCommand) Run(ctx *dep.Ctx, args []string) error {
 			Source:     pc.Ident.Source,
 			Constraint: pc.Constraint,
 		}
-
-		if p.Lock != nil {
-			for i, lp := range p.Lock.P {
-				if lp.Ident() == pc.Ident {
-					p.Lock.P = append(p.Lock.P[:i], p.Lock.P[i+1:]...)
-					break
-				}
-			}
-		}
 	}
 
 	if len(errs) > 0 {
@@ -190,46 +237,7 @@ func (cmd *ensureCommand) Run(ctx *dep.Ctx, args []string) error {
 		return errors.New(buf.String())
 	}
 
-	params := p.MakeParams()
-	// If -update was passed, we want the solver to allow all versions to change
-	params.ChangeAll = cmd.update
-
-	if *verbose {
-		params.Trace = true
-		params.TraceLogger = log.New(os.Stderr, "", 0)
-	}
-
-	params.RootPackageTree, err = gps.ListPackages(p.AbsRoot, string(p.ImportRoot))
-	if err != nil {
-		return errors.Wrap(err, "ensure ListPackage for project")
-	}
-	solver, err := gps.Prepare(params, sm)
-	if err != nil {
-		return errors.Wrap(err, "ensure Prepare")
-	}
-	solution, err := solver.Solve()
-	if err != nil {
-		handleAllTheFailuresOfTheWorld(err)
-		return errors.Wrap(err, "ensure Solve()")
-	}
-
-	sw := dep.SafeWriter{
-		Root:          p.AbsRoot,
-		Manifest:      p.Manifest,
-		Lock:          p.Lock,
-		NewLock:       solution,
-		SourceManager: sm,
-	}
-
-	// check if vendor exists, because if the locks are the same but
-	// vendor does not exist we should write vendor
-	vendorExists, err := dep.IsNonEmptyDir(filepath.Join(sw.Root, "vendor"))
-	if err != nil {
-		return errors.Wrap(err, "ensure vendor is a directory")
-	}
-	writeV := !vendorExists && solution != nil
-
-	return errors.Wrap(sw.WriteAllSafe(writeV), "grouped write of manifest, lock and vendor")
+	return nil
 }
 
 type stringSlice []string
diff --git a/cmd/dep/ensure_test.go b/cmd/dep/ensure_test.go
index d362481884..88311139df 100644
--- a/cmd/dep/ensure_test.go
+++ b/cmd/dep/ensure_test.go
@@ -21,73 +21,36 @@ func TestEnsureOverrides(t *testing.T) {
 	h.TempDir("src")
 	h.Setenv("GOPATH", h.Path("."))
 
-	m := `package main
-
-import (
-	"github.com/Sirupsen/logrus"
-	sthing "github.com/sdboyer/dep-test"
-)
-
-type Baz sthing.Foo
-
-func main() {
-	logrus.Info("hello world")
-}`
-
-	h.TempFile("src/thing/thing.go", m)
+	h.TempCopy("src/thing/thing.go", "ensure/overrides_main.go")
 	h.Cd(h.Path("src/thing"))
 
 	h.Run("init")
-	h.Run("ensure", "-override", "github.com/Sirupsen/logrus@0.11.0")
-
-	expectedManifest := `{
-    "overrides": {
-        "github.com/Sirupsen/logrus": {
-            "version": "0.11.0"
-        }
-    }
-}
-`
-
-	manifest := h.ReadManifest()
-	if manifest != expectedManifest {
-		t.Fatalf("expected %s, got %s", expectedManifest, manifest)
+	h.Run("ensure", "-override", "github.com/carolynvs/go-dep-test@0.1.1")
+
+	goldenManifest := "ensure/overrides_manifest.golden.json"
+	wantManifest := h.GetTestFileString(goldenManifest)
+	gotManifest := h.ReadManifest()
+	if gotManifest != wantManifest {
+		if *test.UpdateGolden {
+			if err := h.WriteTestFile(goldenManifest, string(gotManifest)); err != nil {
+				t.Fatal(err)
+			}
+		} else {
+			t.Fatalf("expected %s, got %s", wantManifest, gotManifest)
+		}
 	}
 
-	sysCommit := h.GetCommit("go.googlesource.com/sys")
-	expectedLock := `{
-    "memo": "57d20ba0289c2df60025bf6127220a5403483251bd5e523a7f9ea17752bd5482",
-    "projects": [
-        {
-            "name": "github.com/Sirupsen/logrus",
-            "version": "v0.11.0",
-            "revision": "d26492970760ca5d33129d2d799e34be5c4782eb",
-            "packages": [
-                "."
-            ]
-        },
-        {
-            "name": "github.com/sdboyer/dep-test",
-            "version": "1.0.0",
-            "revision": "2a3a211e171803acb82d1d5d42ceb53228f51751",
-            "packages": [
-                "."
-            ]
-        },
-        {
-            "name": "golang.org/x/sys",
-            "branch": "master",
-            "revision": "` + sysCommit + `",
-            "packages": [
-                "unix"
-            ]
-        }
-    ]
-}
-`
-	lock := h.ReadLock()
-	if lock != expectedLock {
-		t.Fatalf("expected %s, got %s", expectedLock, lock)
+	goldenLock := "ensure/overrides_lock.golden.json"
+	wantLock := h.GetTestFileString(goldenLock)
+	gotLock := h.ReadLock()
+	if gotLock != wantLock {
+		if *test.UpdateGolden {
+			if err := h.WriteTestFile(goldenLock, string(gotLock)); err != nil {
+				t.Fatal(err)
+			}
+		} else {
+			t.Fatalf("expected %s, got %s", wantLock, gotLock)
+		}
 	}
 }
 
@@ -100,18 +63,7 @@ func TestEnsureEmptyRepoNoArgs(t *testing.T) {
 
 	h.TempDir("src")
 	h.Setenv("GOPATH", h.Path("."))
-
-	m := `package main
-
-import (
-	_ "github.com/jimmysmith95/fixed-version"
-	_ "golang.org/x/sys/unix"
-)
-
-func main() {
-}`
-
-	h.TempFile("src/thing/thing.go", m)
+	h.TempCopy("src/thing/thing.go", "ensure/bare_main.go")
 	h.Cd(h.Path("src/thing"))
 
 	h.Run("init")
@@ -120,43 +72,30 @@ func main() {
 	// make sure vendor exists
 	h.MustExist(h.Path("src/thing/vendor/github.com/jimmysmith95/fixed-version"))
 
-	expectedManifest := `{}
-`
-
-	manifest := h.ReadManifest()
-	if manifest != expectedManifest {
-		t.Fatalf("expected %s, got %s", expectedManifest, manifest)
+	goldenManifest := "ensure/bare_manifest.golden.json"
+	wantManifest := h.GetTestFileString(goldenManifest)
+	gotManifest := h.ReadManifest()
+	if gotManifest != wantManifest {
+		if *test.UpdateGolden {
+			if err := h.WriteTestFile(goldenManifest, string(gotManifest)); err != nil {
+				t.Fatal(err)
+			}
+		} else {
+			t.Fatalf("expected %s, got %s", wantManifest, gotManifest)
+		}
 	}
 
-	sysCommit := h.GetCommit("go.googlesource.com/sys")
-	fixedVersionCommit := h.GetCommit("github.com/jimmysmith95/fixed-version")
-
-	expectedLock := `{
-    "memo": "8a7660015b2473d6d2f4bfdfd0508e6aa8178746559d0a9a90cecfbe6aa47a06",
-    "projects": [
-        {
-            "name": "github.com/jimmysmith95/fixed-version",
-            "version": "v1.0.0",
-            "revision": "` + fixedVersionCommit + `",
-            "packages": [
-                "."
-            ]
-        },
-        {
-            "name": "golang.org/x/sys",
-            "branch": "master",
-            "revision": "` + sysCommit + `",
-            "packages": [
-                "unix"
-            ]
-        }
-    ]
-}
-`
-
-	lock := h.ReadLock()
-	if lock != expectedLock {
-		t.Fatalf("expected %s, got %s", expectedLock, lock)
+	goldenLock := "ensure/bare_lock.golden.json"
+	wantLock := h.GetTestFileString(goldenLock)
+	gotLock := h.ReadLock()
+	if gotLock != wantLock {
+		if *test.UpdateGolden {
+			if err := h.WriteTestFile(goldenLock, string(gotLock)); err != nil {
+				t.Fatal(err)
+			}
+		} else {
+			t.Fatalf("expected %s, got %s", wantLock, gotLock)
+		}
 	}
 }
 
@@ -186,3 +125,44 @@ func TestDeduceConstraint(t *testing.T) {
 		}
 	}
 }
+
+func TestEnsureUpdate(t *testing.T) {
+	test.NeedsExternalNetwork(t)
+	test.NeedsGit(t)
+
+	h := test.NewHelper(t)
+	defer h.Cleanup()
+
+	// Setup up a test project
+	h.TempDir("src")
+	h.Setenv("GOPATH", h.Path("."))
+	h.TempCopy("src/thing/main.go", "ensure/update_main.go")
+	origManifest := "ensure/update_manifest.json"
+	h.TempCopy("src/thing/manifest.json", origManifest)
+	origLock := "ensure/update_lock.json"
+	h.TempCopy("src/thing/lock.json", origLock)
+	h.Cd(h.Path("src/thing"))
+
+	h.Run("ensure", "-update", "github.com/carolynvs/go-dep-test")
+
+	// Verify that the manifest wasn't modified by -update
+	wantManifest := h.GetTestFileString(origManifest)
+	gotManifest := h.ReadManifest()
+	if gotManifest != wantManifest {
+		t.Fatalf("The manifest should not be modified during an update. Expected %s, got %s", origManifest, gotManifest)
+	}
+
+	// Verify the lock matches the expected golden file
+	goldenLock := "ensure/update_lock.golden.json"
+	wantLock := h.GetTestFileString(goldenLock)
+	gotLock := h.ReadLock()
+	if gotLock != wantLock {
+		if *test.UpdateGolden {
+			if err := h.WriteTestFile(goldenLock, string(gotLock)); err != nil {
+				t.Fatal(err)
+			}
+		} else {
+			t.Fatalf("expected %s, got %s", wantLock, gotLock)
+		}
+	}
+}
diff --git a/cmd/dep/testdata/ensure/bare_lock.golden.json b/cmd/dep/testdata/ensure/bare_lock.golden.json
new file mode 100644
index 0000000000..1ad18c9967
--- /dev/null
+++ b/cmd/dep/testdata/ensure/bare_lock.golden.json
@@ -0,0 +1,13 @@
+{
+    "memo": "671164a61abeac1133d1da7f6bb22ed18e6921dfc5f9247b378833833b5a3aca",
+    "projects": [
+        {
+            "name": "github.com/jimmysmith95/fixed-version",
+            "version": "v1.0.0",
+            "revision": "a2d649e0636403a4693cd928f60c56ba7d9cd299",
+            "packages": [
+                "."
+            ]
+        }
+    ]
+}
diff --git a/cmd/dep/testdata/ensure/bare_main.go b/cmd/dep/testdata/ensure/bare_main.go
new file mode 100644
index 0000000000..4c6b76c019
--- /dev/null
+++ b/cmd/dep/testdata/ensure/bare_main.go
@@ -0,0 +1,12 @@
+// Copyright 2016 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package main
+
+import (
+	_ "github.com/jimmysmith95/fixed-version"
+)
+
+func main() {
+}
diff --git a/cmd/dep/testdata/ensure/bare_manifest.golden.json b/cmd/dep/testdata/ensure/bare_manifest.golden.json
new file mode 100644
index 0000000000..0967ef424b
--- /dev/null
+++ b/cmd/dep/testdata/ensure/bare_manifest.golden.json
@@ -0,0 +1 @@
+{}
diff --git a/cmd/dep/testdata/ensure/overrides_lock.golden.json b/cmd/dep/testdata/ensure/overrides_lock.golden.json
new file mode 100644
index 0000000000..2bd94fd2f2
--- /dev/null
+++ b/cmd/dep/testdata/ensure/overrides_lock.golden.json
@@ -0,0 +1,13 @@
+{
+    "memo": "80807a008f7d8d26de122a8c6ad1f4c7286950b32e0488660afc57ccbbc037a1",
+    "projects": [
+        {
+            "name": "github.com/carolynvs/go-dep-test",
+            "version": "0.1.1",
+            "revision": "d15fa4b9d1330a469387f2873399d28ea1c463eb",
+            "packages": [
+                "."
+            ]
+        }
+    ]
+}
diff --git a/cmd/dep/testdata/ensure/overrides_main.go b/cmd/dep/testdata/ensure/overrides_main.go
new file mode 100644
index 0000000000..27fa78605c
--- /dev/null
+++ b/cmd/dep/testdata/ensure/overrides_main.go
@@ -0,0 +1,14 @@
+// Copyright 2016 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package main
+
+import (
+	"fmt"
+	stuff "github.com/carolynvs/go-dep-test"
+)
+
+func main() {
+	fmt.Println(stuff.Thing)
+}
diff --git a/cmd/dep/testdata/ensure/overrides_manifest.golden.json b/cmd/dep/testdata/ensure/overrides_manifest.golden.json
new file mode 100644
index 0000000000..3bfeb541e2
--- /dev/null
+++ b/cmd/dep/testdata/ensure/overrides_manifest.golden.json
@@ -0,0 +1,7 @@
+{
+    "overrides": {
+        "github.com/carolynvs/go-dep-test": {
+            "version": "0.1.1"
+        }
+    }
+}
diff --git a/cmd/dep/testdata/ensure/update_lock.golden.json b/cmd/dep/testdata/ensure/update_lock.golden.json
new file mode 100644
index 0000000000..7239c773c6
--- /dev/null
+++ b/cmd/dep/testdata/ensure/update_lock.golden.json
@@ -0,0 +1,21 @@
+{
+    "memo": "9a5243dd3fa20feeaa20398e7283d6c566532e2af1aae279a010df34793761c5",
+    "projects": [
+        {
+            "name": "github.com/carolynvs/go-dep-test",
+            "version": "0.1.1",
+            "revision": "40691983e4002d3a3f5879cc0f1fe99bedda148c",
+            "packages": [
+                "."
+            ]
+        },
+        {
+            "name": "github.com/pkg/errors",
+            "branch": "v0.7.0",
+            "revision": "01fa4104b9c248c8945d14d9f128454d5b28d595",
+            "packages": [
+                "."
+            ]
+        }
+    ]
+}
diff --git a/cmd/dep/testdata/ensure/update_lock.json b/cmd/dep/testdata/ensure/update_lock.json
new file mode 100644
index 0000000000..907c0372e0
--- /dev/null
+++ b/cmd/dep/testdata/ensure/update_lock.json
@@ -0,0 +1,21 @@
+{
+    "memo": "9a5243dd3fa20feeaa20398e7283d6c566532e2af1aae279a010df34793761c5",
+    "projects": [
+        {
+            "name": "github.com/carolynvs/go-dep-test",
+            "version": "0.1.0",
+            "revision": "b9c5511fa463628e6251554db29a4be161d02aed",
+            "packages": [
+                "."
+            ]
+        },
+        {
+            "name": "github.com/pkg/errors",
+            "branch": "v0.7.0",
+            "revision": "01fa4104b9c248c8945d14d9f128454d5b28d595",
+            "packages": [
+                "."
+            ]
+        }
+    ]
+}
diff --git a/cmd/dep/testdata/ensure/update_main.go b/cmd/dep/testdata/ensure/update_main.go
new file mode 100644
index 0000000000..28e46c204d
--- /dev/null
+++ b/cmd/dep/testdata/ensure/update_main.go
@@ -0,0 +1,20 @@
+// Copyright 2016 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package main
+
+import (
+	"fmt"
+	stuff "github.com/carolynvs/go-dep-test"
+	"github.com/pkg/errors"
+)
+
+func main() {
+	fmt.Println(stuff.Thing)
+	TryToDoSomething()
+}
+
+func TryToDoSomething() error {
+	return errors.New("I tried, Billy. I tried...")
+}
diff --git a/cmd/dep/testdata/ensure/update_manifest.json b/cmd/dep/testdata/ensure/update_manifest.json
new file mode 100644
index 0000000000..fb2ce6c93e
--- /dev/null
+++ b/cmd/dep/testdata/ensure/update_manifest.json
@@ -0,0 +1,7 @@
+{
+    "dependencies": {
+        "github.com/carolynvs/go-dep-test": {
+            "version": "~0.1.0"
+        }
+    }
+}