diff --git a/internal/magic/archive.go b/internal/magic/archive.go
index 8f893e89..fec11f08 100644
--- a/internal/magic/archive.go
+++ b/internal/magic/archive.go
@@ -74,13 +74,21 @@ func CRX(raw []byte, limit uint32) bool {
 }
 
 // Tar matches a (t)ape (ar)chive file.
-//
-// Signature source: https://www.nationalarchives.gov.uk/PRONOM/Format/proFormatSearch.aspx?status=detailReport&id=385&strPageToDisplay=signatures
 func Tar(raw []byte, _ uint32) bool {
+	// The "magic" header field for files in in UStar (POSIX IEEE P1003.1) archives
+	// has the prefix "ustar". The values of the remaining bytes in this field vary
+	// by archiver implementation.
+	if len(raw) >= 512 && bytes.HasPrefix(raw[257:], []byte{0x75, 0x73, 0x74, 0x61, 0x72}) {
+		return true
+	}
+
 	if len(raw) < 256 {
 		return false
 	}
 
+	// The older v7 format has no "magic" field, and therefore must be identified
+	// with heuristics based on legal ranges of values for other header fields:
+	// https://www.nationalarchives.gov.uk/PRONOM/Format/proFormatSearch.aspx?status=detailReport&id=385&strPageToDisplay=signatures
 	rules := []struct {
 		min, max uint8
 		i        int
diff --git a/mimetype_test.go b/mimetype_test.go
index 8d6e645a..cfdde995 100644
--- a/mimetype_test.go
+++ b/mimetype_test.go
@@ -180,12 +180,20 @@ var files = map[string]string{
 	// the timestamps.
 	"not.srt.txt": "text/plain; charset=utf-8",
 	// not.srt.2.txt does not specify milliseconds.
-	"not.srt.2.txt":   "text/plain; charset=utf-8",
-	"svg.1.svg":       "image/svg+xml",
-	"svg.svg":         "image/svg+xml",
-	"swf.swf":         "application/x-shockwave-flash",
-	"tar.tar":         "application/x-tar",
-	"tar.v7.tar":      "application/x-tar",
+	"not.srt.2.txt":  "text/plain; charset=utf-8",
+	"svg.1.svg":      "image/svg+xml",
+	"svg.svg":        "image/svg+xml",
+	"swf.swf":        "application/x-shockwave-flash",
+	"tar.tar":        "application/x-tar",
+	"tar.gnu.tar":    "application/x-tar",
+	"tar.oldgnu.tar": "application/x-tar",
+	"tar.posix.tar":  "application/x-tar",
+	// tar.star.tar was generated with star 1.6.
+	"tar.star.tar":  "application/x-tar",
+	"tar.ustar.tar": "application/x-tar",
+	"tar.v7.tar":    "application/x-tar",
+	// tar.v7-gnu.tar is a v7 tar archive generated with GNU tar 1.29.
+	"tar.v7-gnu.tar":  "application/x-tar",
 	"tcl.tcl":         "text/x-tcl",
 	"tcx.tcx":         "application/vnd.garmin.tcx+xml",
 	"tiff.tiff":       "image/tiff",
diff --git a/testdata/tar.gnu.tar b/testdata/tar.gnu.tar
new file mode 100644
index 00000000..84ee599b
Binary files /dev/null and b/testdata/tar.gnu.tar differ
diff --git a/testdata/tar.oldgnu.tar b/testdata/tar.oldgnu.tar
new file mode 100644
index 00000000..0bd9b86a
Binary files /dev/null and b/testdata/tar.oldgnu.tar differ
diff --git a/testdata/tar.posix.tar b/testdata/tar.posix.tar
new file mode 100644
index 00000000..fad1c10b
Binary files /dev/null and b/testdata/tar.posix.tar differ
diff --git a/testdata/tar.star.tar b/testdata/tar.star.tar
new file mode 100644
index 00000000..3b1e565e
Binary files /dev/null and b/testdata/tar.star.tar differ
diff --git a/testdata/tar.ustar.tar b/testdata/tar.ustar.tar
new file mode 100644
index 00000000..9b023439
Binary files /dev/null and b/testdata/tar.ustar.tar differ
diff --git a/testdata/tar.v7-gnu.tar b/testdata/tar.v7-gnu.tar
new file mode 100644
index 00000000..41dc50ed
Binary files /dev/null and b/testdata/tar.v7-gnu.tar differ