diff --git a/fix/fixer.go b/fix/fixer.go
index bd822a4c2..dceb866fb 100644
--- a/fix/fixer.go
+++ b/fix/fixer.go
@@ -44,6 +44,7 @@ func init() {
 		"vmware-compaction":          new(FixerVMwareCompaction),
 		"clean-image-name":           new(FixerCleanImageName),
 		"spot-price-auto-product":    new(FixerAmazonSpotPriceProductDeprecation),
+		"qemu-disk-size":             new(FixerQEMUDiskSize),
 	}
 
 	FixerOrder = []string{
@@ -71,5 +72,6 @@ func init() {
 		"hyperv-cpu-and-ram",
 		"clean-image-name",
 		"spot-price-auto-product",
+		"qemu-disk-size",
 	}
 }
diff --git a/fix/fixer_qemu_disk_size.go b/fix/fixer_qemu_disk_size.go
new file mode 100644
index 000000000..9a7f15165
--- /dev/null
+++ b/fix/fixer_qemu_disk_size.go
@@ -0,0 +1,53 @@
+package fix
+
+import (
+	"strconv"
+
+	"github.com/mitchellh/mapstructure"
+)
+
+// FixerQEMUDiskSize updates disk_size from a string to int for QEMU builders
+type FixerQEMUDiskSize struct{}
+
+func (FixerQEMUDiskSize) Fix(input map[string]interface{}) (map[string]interface{}, error) {
+	type template struct {
+		Builders []map[string]interface{}
+	}
+
+	// Decode the input into our structure, if we can
+	var tpl template
+	if err := mapstructure.Decode(input, &tpl); err != nil {
+		return nil, err
+	}
+
+	for _, builder := range tpl.Builders {
+		builderTypeRaw, ok := builder["type"]
+		if !ok {
+			continue
+		}
+
+		builderType, ok := builderTypeRaw.(string)
+		if !ok {
+			continue
+		}
+
+		if builderType != "qemu" {
+			continue
+		}
+
+		switch diskSize := builder["disk_size"].(type) {
+		case float64:
+			builder["disk_size"] = strconv.Itoa(int(diskSize)) + "M"
+		case int:
+			builder["disk_size"] = strconv.Itoa(diskSize) + "M"
+		}
+
+	}
+
+	input["builders"] = tpl.Builders
+	return input, nil
+}
+
+func (FixerQEMUDiskSize) Synopsis() string {
+	return `Updates "disk_size" from int to string in QEMU builders.`
+}
diff --git a/fix/fixer_qemu_disk_size_test.go b/fix/fixer_qemu_disk_size_test.go
new file mode 100644
index 000000000..6381dc68d
--- /dev/null
+++ b/fix/fixer_qemu_disk_size_test.go
@@ -0,0 +1,61 @@
+package fix
+
+import (
+	"reflect"
+	"testing"
+)
+
+func TestFixerQEMUDiskSize_impl(t *testing.T) {
+	var _ Fixer = new(FixerQEMUDiskSize)
+}
+
+func TestFixerQEMUDiskSize(t *testing.T) {
+	cases := []struct {
+		Input    map[string]interface{}
+		Expected map[string]interface{}
+	}{
+		{
+			Input: map[string]interface{}{
+				"type":      "qemu",
+				"disk_size": int(40960),
+			},
+
+			Expected: map[string]interface{}{
+				"type":      "qemu",
+				"disk_size": "40960M",
+			},
+		},
+		{
+			Input: map[string]interface{}{
+				"type":      "qemu",
+				"disk_size": float64(50000),
+			},
+
+			Expected: map[string]interface{}{
+				"type":      "qemu",
+				"disk_size": "50000M",
+			},
+		},
+	}
+
+	for _, tc := range cases {
+		var f FixerQEMUDiskSize
+
+		input := map[string]interface{}{
+			"builders": []map[string]interface{}{tc.Input},
+		}
+
+		expected := map[string]interface{}{
+			"builders": []map[string]interface{}{tc.Expected},
+		}
+
+		output, err := f.Fix(input)
+		if err != nil {
+			t.Fatalf("err: %s", err)
+		}
+
+		if !reflect.DeepEqual(output, expected) {
+			t.Fatalf("unexpected: %#v\nexpected: %#v\n", output, expected)
+		}
+	}
+}