diff --git a/oui.c b/oui.c
index 9b9c71caf..bb5e3fe7e 100644
--- a/oui.c
+++ b/oui.c
@@ -27,6 +27,7 @@ const struct tok oui_values[] = {
     { OUI_IANA, "IANA" },
     { OUI_NORTEL, "Nortel Networks SONMP" },
     { OUI_CISCO_90, "Cisco bridged" },
+    { OUI_ITU_T, "ITU-T" },
     { OUI_RFC2684, "Ethernet bridged" },
     { OUI_ATM_FORUM, "ATM Forum" },
     { OUI_CABLE_BPDU, "DOCSIS Spanning Tree" },
diff --git a/oui.h b/oui.h
index 3c824756b..8c8c44994 100644
--- a/oui.h
+++ b/oui.h
@@ -21,6 +21,7 @@ extern const struct tok smi_values[];
 #define OUI_IANA              0x00005E  /* IANA */
 #define OUI_NORTEL            0x000081  /* Nortel SONMP */
 #define OUI_CISCO_90          0x0000f8  /* Cisco bridging */
+#define OUI_ITU_T             0x0019a7  /* International Telecommunication Union - Telecommunication Standardization Sector */
 #define OUI_RFC2684           0x0080c2  /* RFC 2427/2684 bridged Ethernet */
 #define OUI_ATM_FORUM         0x00A03E  /* ATM Forum */
 #define OUI_CABLE_BPDU        0x00E02F  /* DOCSIS spanning tree BPDU */
diff --git a/print-slow.c b/print-slow.c
index 649e2a0fc..6ce3e806d 100644
--- a/print-slow.c
+++ b/print-slow.c
@@ -34,6 +34,7 @@
 #define	SLOW_PROTO_LACP                     1
 #define	SLOW_PROTO_MARKER                   2
 #define SLOW_PROTO_OAM                      3
+#define SLOW_PROTO_OSSP                    10
 
 #define	LACP_VERSION                        1
 #define	MARKER_VERSION                      1
@@ -42,6 +43,7 @@ static const struct tok slow_proto_values[] = {
     { SLOW_PROTO_LACP, "LACP" },
     { SLOW_PROTO_MARKER, "MARKER" },
     { SLOW_PROTO_OAM, "OAM" },
+    { SLOW_PROTO_OSSP, "OSSP" },
     { 0, NULL}
 };
 
@@ -239,6 +241,7 @@ struct lacp_marker_tlv_terminator_t {
 
 static void slow_marker_lacp_print(netdissect_options *, const u_char *, u_int, u_int);
 static void slow_oam_print(netdissect_options *, const u_char *, u_int);
+static void slow_ossp_print(netdissect_options *, const u_char *, u_int);
 
 void
 slow_print(netdissect_options *ndo,
@@ -278,7 +281,8 @@ slow_print(netdissect_options *ndo,
         print_version = 1;
         break;
 
-    case SLOW_PROTO_OAM: /* fall through */
+    case SLOW_PROTO_OAM:
+    case SLOW_PROTO_OSSP:
         print_version = 0;
         break;
 
@@ -313,6 +317,13 @@ slow_print(netdissect_options *ndo,
     default: /* should not happen */
         break;
 
+    case SLOW_PROTO_OSSP:
+        /* skip subtype */
+        len -= 1;
+        pptr += 1;
+        slow_ossp_print(ndo, pptr, len);
+        break;
+
     case SLOW_PROTO_OAM:
         /* skip subtype */
         len -= 1;
@@ -733,3 +744,29 @@ slow_oam_print(netdissect_options *ndo,
 tooshort:
     ND_PRINT("\n\t\t packet is too short");
 }
+
+/*
+ * Print Organization Specific Slow Protocol. (802.3 Annex 57B)
+ */
+static void
+slow_ossp_print(netdissect_options *ndo,
+                const u_char *tptr, u_int tlen)
+{
+    uint32_t oui;
+
+    ND_ICHECKMSG_U("length", tlen, <, 3);
+
+    oui = GET_BE_U_3(tptr);
+    ND_PRINT("\n\tOUI: %s (0x%06x)",
+             tok2str(oui_values, "Unknown", oui),
+             oui);
+    tlen -= 3;
+    tptr += 3;
+
+    print_unknown_data(ndo, tptr, "\n\t", tlen);
+
+    return;
+
+invalid:
+    nd_print_invalid(ndo);
+}
diff --git a/tests/TESTLIST b/tests/TESTLIST
index 25a31efb5..9717efc1e 100644
--- a/tests/TESTLIST
+++ b/tests/TESTLIST
@@ -505,6 +505,7 @@ lldp_mud-v	lldp_mudurl.pcap	lldp_mudurl-v.out	-e -v
 lldp_mud-vv	lldp_mudurl.pcap	lldp_mudurl-vv.out	-e -vv
 lldp_8021_linkagg-v  lldp_8021_linkagg.pcap lldp_8021_linkagg-v.out  -v
 lldp_8021_linkagg-vv lldp_8021_linkagg.pcap lldp_8021_linkagg-vv.out -vv
+slow-ossp	slow-ossp.pcap	slow-ossp.out	-v
 # fuzzed pcap
 udld-inf-loop-1-v  udld-inf-loop-1.pcapng  udld-inf-loop-1-v.out  -v
 
diff --git a/tests/slow-ossp.out b/tests/slow-ossp.out
new file mode 100644
index 000000000..06f9dca90
--- /dev/null
+++ b/tests/slow-ossp.out
@@ -0,0 +1,5 @@
+    1  2025-09-23 15:00:00.000000 OSSP, length 52
+	OUI: ITU-T (0x0019a7)
+	0x0000:  0001 1000 0000 0100 0404 0000 0000 0000
+	0x0010:  0000 0000 0000 0000 0000 0000 0000 0000
+	0x0020:  0000 0000 0000 0000 0000 0000 0000 0000
diff --git a/tests/slow-ossp.pcap b/tests/slow-ossp.pcap
new file mode 100644
index 000000000..7e052503d
Binary files /dev/null and b/tests/slow-ossp.pcap differ