diff --git a/docs/src/content/docs/reference/open-telemetry.md b/docs/src/content/docs/reference/open-telemetry.md
index c2ffdf1230..6aae6335af 100644
--- a/docs/src/content/docs/reference/open-telemetry.md
+++ b/docs/src/content/docs/reference/open-telemetry.md
@@ -107,7 +107,7 @@ When `observability.otlp` is configured, gh-aw injects:
 | Variable | Description |
 | --- | --- |
 | `OTEL_EXPORTER_OTLP_HEADERS` | Comma-separated `key=value` headers for the first endpoint (when headers are configured). |
-| `OTEL_SERVICE_NAME` | Always `gh-aw`. |
+| `OTEL_SERVICE_NAME` | `gh-aw.<sanitized-workflow-id>` when `WorkflowID` is available (for example, `Repo Triage/Weekly` → `gh-aw.repo-triage-weekly`); falls back to sanitized workflow name when only the name is available, otherwise `gh-aw`. |
 | `GH_AW_OTLP_ENDPOINTS` | JSON array of all endpoint entries, used by gh-aw JavaScript span exporters for fan-out. |
 | `GH_AW_OTLP_IF_MISSING` | Set to `warn` or `ignore` when `observability.otlp.if-missing` is configured. |
 | `COPILOT_OTEL_FILE_EXPORTER_PATH` | Path for Copilot CLI span output (`/tmp/gh-aw/copilot-otel.jsonl`). |
diff --git a/pkg/workflow/observability_otlp.go b/pkg/workflow/observability_otlp.go
index ec8b3e366e..6e4ace56e2 100644
--- a/pkg/workflow/observability_otlp.go
+++ b/pkg/workflow/observability_otlp.go
@@ -399,12 +399,14 @@ func (c *Compiler) injectOTLPConfig(workflowData *WorkflowData) {
 
 	firstEndpoint := entries[0].URL
 	firstHeaders := entries[0].Headers
+	serviceName := otelServiceName(workflowData)
 	ifMissingMode := getOTLPIfMissingMode(workflowData.ParsedFrontmatter, workflowData.RawFrontmatter)
 
 	// 2. Inject OTEL env vars into the workflow-level env: block.
-	//    OTEL_EXPORTER_OTLP_ENDPOINT and OTEL_SERVICE_NAME are set to the first
-	//    endpoint for backward compatibility (MCP gateway, legacy scripts).
-	otlpEnvLines := fmt.Sprintf("  OTEL_EXPORTER_OTLP_ENDPOINT: %s\n  OTEL_SERVICE_NAME: gh-aw", firstEndpoint)
+	//    OTEL_EXPORTER_OTLP_ENDPOINT is set to the first endpoint for backward
+	//    compatibility (MCP gateway, legacy scripts). OTEL_SERVICE_NAME is
+	//    workflow-specific when WorkflowID is available.
+	otlpEnvLines := fmt.Sprintf("  OTEL_EXPORTER_OTLP_ENDPOINT: %s\n  OTEL_SERVICE_NAME: %s", firstEndpoint, serviceName)
 
 	// 3. Inject per-endpoint headers env vars.
 	//    OTEL_EXPORTER_OTLP_HEADERS = first endpoint headers (backward compat).
@@ -444,3 +446,28 @@ func (c *Compiler) injectOTLPConfig(workflowData *WorkflowData) {
 	workflowData.OTLPHeaders = firstHeaders
 	workflowData.OTLPEndpoints = encodeOTLPEndpoints(entries)
 }
+
+func otelServiceName(workflowData *WorkflowData) string {
+	const defaultServiceName = "gh-aw"
+	if workflowData == nil {
+		return defaultServiceName
+	}
+
+	// Prefer the file-based WorkflowID to avoid collisions across workflows that
+	// may share display names; fall back to workflow Name when WorkflowID is
+	// unavailable (for workflow_call-only contexts).
+	workflowIDOrName := strings.TrimSpace(workflowData.WorkflowID)
+	if workflowIDOrName == "" {
+		workflowIDOrName = workflowData.Name
+	}
+
+	// SanitizeWorkflowName lowercases the workflow identifier and converts
+	// separators/special characters (spaces, slashes, etc.) to hyphens so the
+	// service suffix is stable and backend-friendly.
+	sanitizedWorkflowName := SanitizeWorkflowName(workflowIDOrName)
+	if sanitizedWorkflowName == "" {
+		return defaultServiceName
+	}
+
+	return defaultServiceName + "." + sanitizedWorkflowName
+}
diff --git a/pkg/workflow/observability_otlp_test.go b/pkg/workflow/observability_otlp_test.go
index feb3210fd5..490702a2fe 100644
--- a/pkg/workflow/observability_otlp_test.go
+++ b/pkg/workflow/observability_otlp_test.go
@@ -358,9 +358,10 @@ func TestInjectOTLPConfig(t *testing.T) {
 		assert.Equal(t, 1, strings.Count(wd.Env, "env:"), "should have exactly one env: key")
 	})
 
-	t.Run("OTEL_SERVICE_NAME is always gh-aw", func(t *testing.T) {
+	t.Run("OTEL_SERVICE_NAME includes sanitized workflow ID when available", func(t *testing.T) {
 		c := newCompiler()
 		wd := &WorkflowData{
+			WorkflowID: "Repo Triage/Weekly",
 			ParsedFrontmatter: &FrontmatterConfig{
 				Observability: &ObservabilityConfig{
 					OTLP: &OTLPConfig{Endpoint: "https://otel.corp.com"},
@@ -368,7 +369,7 @@ func TestInjectOTLPConfig(t *testing.T) {
 			},
 		}
 		c.injectOTLPConfig(wd)
-		assert.Contains(t, wd.Env, "OTEL_SERVICE_NAME: gh-aw", "service name should always be gh-aw")
+		assert.Contains(t, wd.Env, "OTEL_SERVICE_NAME: gh-aw.repo-triage-weekly", "service name should include sanitized workflow ID")
 	})
 
 	t.Run("injects OTEL_EXPORTER_OTLP_HEADERS when headers are configured", func(t *testing.T) {
@@ -659,6 +660,36 @@ func TestInjectOTLPConfig_HeadersPresenceAfterInjection(t *testing.T) {
 	})
 }
 
+func TestOTELServiceName(t *testing.T) {
+	t.Run("uses workflow-specific service name when workflow ID is present", func(t *testing.T) {
+		got := otelServiceName(&WorkflowData{WorkflowID: "Repo Triage/Weekly"})
+		assert.Equal(t, "gh-aw.repo-triage-weekly", got, "should use WorkflowID as service name suffix when present")
+	})
+
+	t.Run("falls back to workflow name when workflow ID is empty", func(t *testing.T) {
+		got := otelServiceName(&WorkflowData{Name: "Repo Triage/Weekly"})
+		assert.Equal(t, "gh-aw.repo-triage-weekly", got, "should fall back to workflow name when WorkflowID is empty")
+	})
+
+	t.Run("workflow ID takes precedence over workflow name", func(t *testing.T) {
+		got := otelServiceName(&WorkflowData{
+			WorkflowID: "Unique Workflow ID",
+			Name:       "Shared Display Name",
+		})
+		assert.Equal(t, "gh-aw.unique-workflow-id", got, "should prefer WorkflowID over workflow name when both are present")
+	})
+
+	t.Run("falls back when workflow ID and name are empty", func(t *testing.T) {
+		got := otelServiceName(&WorkflowData{})
+		assert.Equal(t, "gh-aw", got, "should return default service name when WorkflowID and name are empty")
+	})
+
+	t.Run("falls back when workflow data is nil", func(t *testing.T) {
+		got := otelServiceName(nil)
+		assert.Equal(t, "gh-aw", got, "should return default service name when workflow data is nil")
+	})
+}
+
 // TestInjectOTLPConfig_OTLPEndpointField verifies that injectOTLPConfig sets workflowData.OTLPEndpoint
 // so that downstream code (buildMCPGatewayConfig, mcp_setup_generator) can use it as the
 // single source of truth for "is OTLP configured?" without re-reading raw frontmatter.