diff --git a/docker_test.go b/docker_test.go
new file mode 100644
index 0000000..d78c2e6
--- /dev/null
+++ b/docker_test.go
@@ -0,0 +1,37 @@
+package purl_test
+
+import (
+	"testing"
+
+	"github.com/git-pkgs/purl"
+)
+
+func TestDockerImagePURLs(t *testing.T) {
+	tests := []struct {
+		name, version, want string
+	}{
+		{"postgres", "16", "pkg:docker/postgres@16"},
+		{"example/image", "latest", "pkg:docker/example/image@latest"},
+		{"ghcr.io/example/image", "2", "pkg:docker/ghcr.io/example/image@2"},
+		{"registry.example:5000/team/image", "1", "pkg:docker/registry.example:5000/team/image@1"},
+		{"ghcr.io/example/image", "sha256:abc123", "pkg:docker/ghcr.io/example/image@sha256:abc123"},
+		{"ghcr.io/example/image", "", "pkg:docker/ghcr.io/example/image"},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name+"@"+tt.version, func(t *testing.T) {
+			if got := purl.BuildPURLString("docker", tt.name, tt.version, ""); got != tt.want {
+				t.Errorf("BuildPURLString = %q, want %q", got, tt.want)
+			}
+			if got := purl.MakePURLString("docker", tt.name, tt.version); got != tt.want {
+				t.Errorf("MakePURLString = %q, want %q", got, tt.want)
+			}
+			got := purl.MakePURL("docker", tt.name, tt.version)
+			if got == nil {
+				t.Fatal("MakePURL returned nil")
+			}
+			if got.String() != tt.want {
+				t.Errorf("MakePURL = %q, want %q", got.String(), tt.want)
+			}
+		})
+	}
+}
diff --git a/makepurl.go b/makepurl.go
index 8712d03..7cfb963 100644
--- a/makepurl.go
+++ b/makepurl.go
@@ -210,7 +210,7 @@ func splitNamespace(ecosystem, name string) (namespace, pkgName string, ok bool)
 				pkgName = name[i+1:]
 			}
 		}
-	case ecosystemGolang:
+	case ecosystemGolang, "docker":
 		if i := strings.LastIndex(name, "/"); i > 0 {
 			namespace = name[:i]
 			pkgName = name[i+1:]