diff --git a/pkg/sfu/utils/helpers.go b/pkg/sfu/utils/helpers.go
index 7ce7eaac8..c1a9da50a 100644
--- a/pkg/sfu/utils/helpers.go
+++ b/pkg/sfu/utils/helpers.go
@@ -17,6 +17,8 @@ package utils
 import (
 	"errors"
 	"fmt"
+	"strconv"
+	"strings"
 
 	"github.com/pion/interceptor"
 	"github.com/pion/rtp"
@@ -47,12 +49,17 @@ func CodecParametersFuzzySearch(needle webrtc.RTPCodecParameters, haystack []web
 	return webrtc.RTPCodecParameters{}, webrtc.ErrCodecNotFound
 }
 
-// Given a CodecParameters find the RTX CodecParameters if one exists
+// Given a CodecParameters find the RTX CodecParameters if one exists.
+// The RTX fmtp line can carry other parameters next to apt, for example
+// "apt=96;rtx-time=3000" (RFC 4588), so only the apt value is compared.
 func FindRTXPayloadType(needle webrtc.PayloadType, haystack []webrtc.RTPCodecParameters) webrtc.PayloadType {
-	aptStr := fmt.Sprintf("apt=%d", needle)
+	aptStr := strconv.Itoa(int(needle))
 	for _, c := range haystack {
-		if aptStr == c.SDPFmtpLine {
-			return c.PayloadType
+		for param := range strings.SplitSeq(c.SDPFmtpLine, ";") {
+			key, value, found := strings.Cut(param, "=")
+			if found && strings.EqualFold(strings.TrimSpace(key), "apt") && strings.TrimSpace(value) == aptStr {
+				return c.PayloadType
+			}
 		}
 	}
 
diff --git a/pkg/sfu/utils/helpers_test.go b/pkg/sfu/utils/helpers_test.go
new file mode 100644
index 000000000..c2c30bb3e
--- /dev/null
+++ b/pkg/sfu/utils/helpers_test.go
@@ -0,0 +1,55 @@
+// Copyright 2026 LiveKit, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package utils
+
+import (
+	"testing"
+
+	"github.com/pion/webrtc/v4"
+	"github.com/stretchr/testify/require"
+
+	"github.com/livekit/protocol/codecs/mime"
+)
+
+func TestFindRTXPayloadType(t *testing.T) {
+	rtx := func(pt webrtc.PayloadType, fmtp string) webrtc.RTPCodecParameters {
+		return webrtc.RTPCodecParameters{
+			RTPCodecCapability: webrtc.RTPCodecCapability{MimeType: mime.MimeTypeRTX.String(), ClockRate: 90000, SDPFmtpLine: fmtp},
+			PayloadType:        pt,
+		}
+	}
+	vp8 := webrtc.RTPCodecParameters{
+		RTPCodecCapability: webrtc.RTPCodecCapability{MimeType: mime.MimeTypeVP8.String(), ClockRate: 90000},
+		PayloadType:        96,
+	}
+
+	tests := []struct {
+		name     string
+		haystack []webrtc.RTPCodecParameters
+		expected webrtc.PayloadType
+	}{
+		{name: "apt only", haystack: []webrtc.RTPCodecParameters{vp8, rtx(97, "apt=96")}, expected: 97},
+		{name: "apt with rtx-time", haystack: []webrtc.RTPCodecParameters{vp8, rtx(97, "apt=96;rtx-time=3000")}, expected: 97},
+		{name: "rtx-time before apt", haystack: []webrtc.RTPCodecParameters{vp8, rtx(97, "rtx-time=3000; apt=96")}, expected: 97},
+		{name: "other codec", haystack: []webrtc.RTPCodecParameters{vp8, rtx(99, "apt=98"), rtx(97, "apt=96")}, expected: 97},
+		{name: "apt prefix", haystack: []webrtc.RTPCodecParameters{vp8, rtx(97, "apt=960")}, expected: 0},
+		{name: "no rtx", haystack: []webrtc.RTPCodecParameters{vp8}, expected: 0},
+	}
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+			require.Equal(t, tc.expected, FindRTXPayloadType(96, tc.haystack))
+		})
+	}
+}