diff --git a/internal/provider/append_resource.go b/internal/provider/append_resource.go
index 190f2ef..a3cc178 100644
--- a/internal/provider/append_resource.go
+++ b/internal/provider/append_resource.go
@@ -25,8 +25,10 @@ import (
 	"github.com/hashicorp/terraform-plugin-log/tflog"
 )
 
-var _ resource.Resource = &AppendResource{}
-var _ resource.ResourceWithImportState = &AppendResource{}
+var (
+	_ resource.Resource                = &AppendResource{}
+	_ resource.ResourceWithImportState = &AppendResource{}
+)
 
 func NewAppendResource() resource.Resource {
 	return &AppendResource{}
@@ -198,7 +200,10 @@ func (r *AppendResource) doAppend(ctx context.Context, data *AppendResourceModel
 	if err != nil {
 		return nil, []diag.Diagnostic{diag.NewErrorDiagnostic("Unable to parse base image", fmt.Sprintf("Unable to parse base image %q, got error: %s", data.BaseImage.ValueString(), err))}
 	}
-	img, err := remote.Image(baseref, r.popts.withContext(ctx)...)
+
+	ropts := r.popts.withContext(ctx)
+
+	desc, err := remote.Get(baseref, ropts...)
 	if err != nil {
 		return nil, []diag.Diagnostic{diag.NewErrorDiagnostic("Unable to fetch base image", fmt.Sprintf("Unable to fetch base image %q, got error: %s", data.BaseImage.ValueString(), err))}
 	}
@@ -248,19 +253,64 @@ func (r *AppendResource) doAppend(ctx context.Context, data *AppendResourceModel
 		})
 	}
 
-	img, err = mutate.Append(img, adds...)
-	if err != nil {
-		return nil, []diag.Diagnostic{diag.NewErrorDiagnostic("Unable to append layers", fmt.Sprintf("Unable to append layers, got error: %s", err))}
-	}
+	var d name.Digest
 
-	dig, err := img.Digest()
-	if err != nil {
-		return nil, []diag.Diagnostic{diag.NewErrorDiagnostic("Unable to get image digest", fmt.Sprintf("Unable to get image digest, got error: %s", err))}
-	}
+	if desc.MediaType.IsIndex() {
+		baseidx, err := desc.ImageIndex()
+		if err != nil {
+			return nil, []diag.Diagnostic{diag.NewErrorDiagnostic("Unable to read image index", fmt.Sprintf("Unable to read image index for ref %q, got error: %s", data.BaseImage.ValueString(), err))}
+		}
+
+		baseimf, err := baseidx.IndexManifest()
+		if err != nil {
+			return nil, []diag.Diagnostic{diag.NewErrorDiagnostic("Unable to read image index manifest", fmt.Sprintf("Unable to read image index manifest for ref %q, got error: %s", data.BaseImage.ValueString(), err))}
+		}
+
+		// get the image for each platform
+		for _, p := range baseimf.Manifests {
+			baseimg, err := baseidx.Image(p.Digest)
+			if err != nil {
+				return nil, []diag.Diagnostic{diag.NewErrorDiagnostic("Unable to load image", fmt.Sprintf("Unable to load image for ref %q, got error: %s", data.BaseImage.ValueString(), err))}
+			}
+
+			img, err := mutate.Append(baseimg, adds...)
+			if err != nil {
+				return nil, []diag.Diagnostic{diag.NewErrorDiagnostic("Unable to append layers", fmt.Sprintf("Unable to append layers, got error: %s", err))}
+			}
 
-	d := baseref.Context().Digest(dig.String())
-	if err := remote.Write(d, img, r.popts.withContext(ctx)...); err != nil {
-		return nil, []diag.Diagnostic{diag.NewErrorDiagnostic("Unable to push image", fmt.Sprintf("Unable to push image, got error: %s", err))}
+			baseidx = mutate.AppendManifests(baseidx, mutate.IndexAddendum{Add: img, Descriptor: p})
+
+			dig, err := baseidx.Digest()
+			if err != nil {
+				return nil, []diag.Diagnostic{diag.NewErrorDiagnostic("Unable to get image digest", fmt.Sprintf("Unable to get image digest, got error: %s", err))}
+			}
+
+			d = baseref.Context().Digest(dig.String())
+			if err := remote.WriteIndex(d, baseidx, r.popts.withContext(ctx)...); err != nil {
+				return nil, []diag.Diagnostic{diag.NewErrorDiagnostic("Unable to push image", fmt.Sprintf("Unable to push image, got error: %s", err))}
+			}
+		}
+
+	} else if desc.MediaType.IsImage() {
+		baseimg, err := remote.Image(baseref, ropts...)
+		if err != nil {
+			return nil, []diag.Diagnostic{diag.NewErrorDiagnostic("Unable to fetch base image", fmt.Sprintf("Unable to fetch base image %q, got error: %s", data.BaseImage.ValueString(), err))}
+		}
+
+		img, err := mutate.Append(baseimg, adds...)
+		if err != nil {
+			return nil, []diag.Diagnostic{diag.NewErrorDiagnostic("Unable to append layers", fmt.Sprintf("Unable to append layers, got error: %s", err))}
+		}
+
+		dig, err := img.Digest()
+		if err != nil {
+			return nil, []diag.Diagnostic{diag.NewErrorDiagnostic("Unable to get image digest", fmt.Sprintf("Unable to get image digest, got error: %s", err))}
+		}
+
+		d = baseref.Context().Digest(dig.String())
+		if err := remote.Write(d, img, r.popts.withContext(ctx)...); err != nil {
+			return nil, []diag.Diagnostic{diag.NewErrorDiagnostic("Unable to push image", fmt.Sprintf("Unable to push image, got error: %s", err))}
+		}
 	}
 
 	// Write logs using the tflog package
diff --git a/internal/provider/append_resource_test.go b/internal/provider/append_resource_test.go
index 1e832aa..83f9a12 100644
--- a/internal/provider/append_resource_test.go
+++ b/internal/provider/append_resource_test.go
@@ -7,6 +7,7 @@ import (
 
 	ocitesting "github.com/chainguard-dev/terraform-provider-oci/testing"
 	"github.com/google/go-containerregistry/pkg/crane"
+	"github.com/google/go-containerregistry/pkg/name"
 	"github.com/google/go-containerregistry/pkg/v1/random"
 	"github.com/google/go-containerregistry/pkg/v1/remote"
 	"github.com/google/go-containerregistry/pkg/v1/validate"
@@ -90,4 +91,51 @@ func TestAccAppendResource(t *testing.T) {
 			// Delete testing automatically occurs in TestCase
 		},
 	})
+
+	// Push an index to the local registry.
+	ref3 := repo.Tag("3")
+	idx1, err := random.Index(3, 1, 3)
+	if err != nil {
+		t.Fatalf("failed to create index: %v", err)
+	}
+	if err := remote.WriteIndex(ref3, idx1); err != nil {
+		t.Fatalf("failed to write index: %v", err)
+	}
+
+	resource.Test(t, resource.TestCase{
+		PreCheck:                 func() { testAccPreCheck(t) },
+		ProtoV6ProviderFactories: testAccProtoV6ProviderFactories,
+		Steps: []resource.TestStep{
+			// Create and Read testing
+			{
+				Config: fmt.Sprintf(`resource "oci_append" "test" {
+        base_image = %q
+        layers = [{
+          files = {
+            "/usr/local/test.txt" = { contents = "hello world" }
+          }
+        }]
+      }`, ref3),
+				Check: resource.ComposeAggregateTestCheckFunc(
+					resource.TestCheckResourceAttr("oci_append.test", "base_image", ref3.String()),
+					resource.TestMatchResourceAttr("oci_append.test", "id", regexp.MustCompile(`/test@sha256:[0-9a-f]{64}$`)),
+					resource.TestCheckFunc(func(s *terraform.State) error {
+						rs := s.RootModule().Resources["oci_append.test"]
+						ref, err := name.ParseReference(rs.Primary.Attributes["image_ref"])
+						if err != nil {
+							return fmt.Errorf("failed to parse reference: %v", err)
+						}
+						idx, err := remote.Index(ref)
+						if err != nil {
+							return fmt.Errorf("failed to pull image: %v", err)
+						}
+						if err := validate.Index(idx); err != nil {
+							return fmt.Errorf("failed to validate image: %v", err)
+						}
+						return nil
+					}),
+				),
+			},
+		},
+	})
 }