diff --git a/modules/rtp_rtcp/source/rtcp_receiver.h b/modules/rtp_rtcp/source/rtcp_receiver.h
index a9f602f845..918d349392 100644
--- a/modules/rtp_rtcp/source/rtcp_receiver.h
+++ b/modules/rtp_rtcp/source/rtcp_receiver.h
@@ -15,6 +15,7 @@
 #include <map>
 #include <set>
 #include <string>
+#include <unordered_map>
 #include <vector>
 
 #include "api/array_view.h"
@@ -145,6 +146,11 @@ class RTCPReceiver final {
   struct TmmbrInformation;
   struct RrtrInformation;
   struct LastFirStatus;
+
+  // TODO(boivie): `ReportBlockDataMap` and `ReportBlockMap` should be converted
+  // to std::unordered_map, but as there are too many tests that assume a
+  // specific order, it's not easily done.
+
   // RTCP report blocks mapped by remote SSRC.
   using ReportBlockDataMap = std::map<uint32_t, ReportBlockData>;
   // RTCP report blocks map mapped by source SSRC.
@@ -273,7 +279,7 @@ class RTCPReceiver final {
   std::list<RrtrInformation> received_rrtrs_
       RTC_GUARDED_BY(rtcp_receiver_lock_);
   // Received RRTR information mapped by remote ssrc.
-  std::map<uint32_t, std::list<RrtrInformation>::iterator>
+  std::unordered_map<uint32_t, std::list<RrtrInformation>::iterator>
       received_rrtrs_ssrc_it_ RTC_GUARDED_BY(rtcp_receiver_lock_);
 
   // Estimated rtt, zero when there is no valid estimate.
@@ -282,11 +288,11 @@ class RTCPReceiver final {
 
   int64_t oldest_tmmbr_info_ms_ RTC_GUARDED_BY(rtcp_receiver_lock_);
   // Mapped by remote ssrc.
-  std::map<uint32_t, TmmbrInformation> tmmbr_infos_
+  std::unordered_map<uint32_t, TmmbrInformation> tmmbr_infos_
       RTC_GUARDED_BY(rtcp_receiver_lock_);
 
   ReportBlockMap received_report_blocks_ RTC_GUARDED_BY(rtcp_receiver_lock_);
-  std::map<uint32_t, LastFirStatus> last_fir_
+  std::unordered_map<uint32_t, LastFirStatus> last_fir_
       RTC_GUARDED_BY(rtcp_receiver_lock_);
 
   // The last time we received an RTCP Report block for this module.
diff --git a/modules/rtp_rtcp/source/rtcp_receiver_unittest.cc b/modules/rtp_rtcp/source/rtcp_receiver_unittest.cc
index 5739c51f65..068a110771 100644
--- a/modules/rtp_rtcp/source/rtcp_receiver_unittest.cc
+++ b/modules/rtp_rtcp/source/rtcp_receiver_unittest.cc
@@ -51,6 +51,7 @@ using rtcp::ReceiveTimeInfo;
 using ::testing::_;
 using ::testing::AllOf;
 using ::testing::ElementsAreArray;
+using ::testing::Eq;
 using ::testing::Field;
 using ::testing::InSequence;
 using ::testing::IsEmpty;
@@ -1266,16 +1267,17 @@ TEST(RtcpReceiverTest, TmmbrThreeConstraintsTimeOut) {
     mocks.clock.AdvanceTimeMilliseconds(5000);
   }
   // It is now starttime + 15.
-  std::vector<rtcp::TmmbItem> candidate_set = receiver.TmmbrReceived();
-  ASSERT_EQ(3u, candidate_set.size());
-  EXPECT_EQ(30000U, candidate_set[0].bitrate_bps());
+  EXPECT_THAT(receiver.TmmbrReceived(),
+              AllOf(SizeIs(3),
+                    Each(Property(&rtcp::TmmbItem::bitrate_bps, Eq(30'000U)))));
 
   // We expect the timeout to be 25 seconds. Advance the clock by 12
   // seconds, timing out the first packet.
   mocks.clock.AdvanceTimeMilliseconds(12000);
-  candidate_set = receiver.TmmbrReceived();
-  ASSERT_EQ(2u, candidate_set.size());
-  EXPECT_EQ(kSenderSsrc + 1, candidate_set[0].ssrc());
+  EXPECT_THAT(receiver.TmmbrReceived(),
+              UnorderedElementsAre(
+                  Property(&rtcp::TmmbItem::ssrc, Eq(kSenderSsrc + 1)),
+                  Property(&rtcp::TmmbItem::ssrc, Eq(kSenderSsrc + 2))));
 }
 
 TEST(RtcpReceiverTest, Callbacks) {