diff --git a/features/messages/impl/src/main/kotlin/io/element/android/features/messages/impl/timeline/factories/event/TimelineItemEventFactory.kt b/features/messages/impl/src/main/kotlin/io/element/android/features/messages/impl/timeline/factories/event/TimelineItemEventFactory.kt
index af3e18e3cc..6cd6b66cf1 100644
--- a/features/messages/impl/src/main/kotlin/io/element/android/features/messages/impl/timeline/factories/event/TimelineItemEventFactory.kt
+++ b/features/messages/impl/src/main/kotlin/io/element/android/features/messages/impl/timeline/factories/event/TimelineItemEventFactory.kt
@@ -28,10 +28,12 @@ import io.element.android.libraries.dateformatter.api.DateFormatterMode
 import io.element.android.libraries.designsystem.components.avatar.AvatarData
 import io.element.android.libraries.designsystem.components.avatar.AvatarSize
 import io.element.android.libraries.matrix.api.MatrixClient
+import io.element.android.libraries.matrix.api.core.UserId
 import io.element.android.libraries.matrix.api.permalink.PermalinkParser
 import io.element.android.libraries.matrix.api.room.RoomMember
 import io.element.android.libraries.matrix.api.timeline.MatrixTimelineItem
 import io.element.android.libraries.matrix.api.timeline.item.EventThreadInfo
+import io.element.android.libraries.matrix.api.timeline.item.event.ProfileDetails
 import io.element.android.libraries.matrix.api.timeline.item.event.getAvatarUrl
 import io.element.android.libraries.matrix.api.timeline.item.event.getDisambiguatedDisplayName
 import io.element.android.libraries.matrix.ui.messages.reply.map
@@ -64,7 +66,7 @@ class TimelineItemEventFactory(
         val currentSender = currentTimelineItem.event.sender
         val groupPosition =
             computeGroupPosition(currentTimelineItem, timelineItems, index)
-        val senderProfile = currentTimelineItem.event.senderProfile
+        val senderProfile = currentTimelineItem.event.senderProfile.orFallbackTo(roomMembers, currentSender)
         val sentTime = dateFormatter.format(
             timestamp = currentTimelineItem.event.timestamp,
             mode = DateFormatterMode.TimeOnly,
@@ -138,11 +140,32 @@ class TimelineItemEventFactory(
         roomMembers: List<RoomMember>,
         renderReadReceipts: Boolean,
     ): TimelineItem.Event {
+        val senderProfile = receivedMatrixTimelineItem.event.senderProfile.orFallbackTo(roomMembers, timelineItem.senderId)
         return timelineItem.copy(
+            senderProfile = senderProfile,
+            senderAvatar = timelineItem.senderAvatar.copy(
+                name = senderProfile.getDisambiguatedDisplayName(timelineItem.senderId),
+                url = senderProfile.getAvatarUrl(),
+            ),
             readReceiptState = receivedMatrixTimelineItem.computeReadReceiptState(roomMembers, renderReadReceipts)
         )
     }
 
+    /**
+     * The timeline only knows the profiles the SDK has resolved, so a sender it has nothing for is rendered as a raw
+     * user ID. The room member list usually knows that user, so use it rather than showing the ID.
+     */
+    private fun ProfileDetails.orFallbackTo(roomMembers: List<RoomMember>, senderId: UserId): ProfileDetails {
+        if (this is ProfileDetails.Ready) return this
+        val member = roomMembers.find { it.userId == senderId } ?: return this
+        return ProfileDetails.Ready(
+            displayName = member.displayName,
+            displayNameAmbiguous = member.isNameAmbiguous,
+            avatarUrl = member.avatarUrl,
+            displayedStatus = member.displayedStatus,
+        )
+    }
+
     private fun MatrixTimelineItem.Event.computeReactionsState(): TimelineItemReactions {
         if (!config.computeReactions) {
             return TimelineItemReactions(reactions = persistentListOf())
diff --git a/features/messages/impl/src/test/kotlin/io/element/android/features/messages/impl/timeline/factories/TimelineItemsFactoryTest.kt b/features/messages/impl/src/test/kotlin/io/element/android/features/messages/impl/timeline/factories/TimelineItemsFactoryTest.kt
index f93c8f196e..3c51fc88ef 100644
--- a/features/messages/impl/src/test/kotlin/io/element/android/features/messages/impl/timeline/factories/TimelineItemsFactoryTest.kt
+++ b/features/messages/impl/src/test/kotlin/io/element/android/features/messages/impl/timeline/factories/TimelineItemsFactoryTest.kt
@@ -16,7 +16,10 @@ import io.element.android.features.messages.impl.timeline.model.event.TimelineIt
 import io.element.android.libraries.matrix.api.core.UniqueId
 import io.element.android.libraries.matrix.api.timeline.MatrixTimelineItem
 import io.element.android.libraries.matrix.api.timeline.item.event.OtherMessageType
+import io.element.android.libraries.matrix.api.timeline.item.event.ProfileDetails
 import io.element.android.libraries.matrix.test.A_USER_ID
+import io.element.android.libraries.matrix.test.A_USER_ID_2
+import io.element.android.libraries.matrix.test.room.aRoomMember
 import io.element.android.libraries.matrix.test.timeline.aMessageContent
 import io.element.android.libraries.matrix.test.timeline.anEventTimelineItem
 import kotlinx.coroutines.test.TestScope
@@ -128,6 +131,74 @@ class TimelineItemsFactoryTest {
         }
     }
 
+    @Test
+    fun `a sender the timeline knows nothing about is named from the room member list`() = runTest {
+        val factory = aTimelineItemsFactory(
+            config = TimelineItemsFactoryConfig(
+                computeReadReceipts = false,
+                computeReactions = false,
+            )
+        )
+        val items = listOf(
+            MatrixTimelineItem.Event(
+                uniqueId = UniqueId("event-0"),
+                event = anEventTimelineItem(
+                    sender = A_USER_ID,
+                    senderProfile = ProfileDetails.Unavailable,
+                    content = aMessageContent(body = "A regular message"),
+                ),
+            ),
+        )
+        factory.timelineItems.test {
+            factory.replaceWith(
+                timelineItems = items,
+                roomMembers = listOf(aRoomMember(userId = A_USER_ID, displayName = "Alice")),
+                renderReadReceipts = false,
+            )
+            val event = awaitItem().filterIsInstance<TimelineItem.Event>().single()
+            assertThat(event.senderProfile).isEqualTo(
+                ProfileDetails.Ready(
+                    displayName = "Alice",
+                    displayNameAmbiguous = false,
+                    avatarUrl = null,
+                    displayedStatus = null,
+                )
+            )
+            assertThat(event.senderAvatar.name).isEqualTo("Alice")
+            cancelAndIgnoreRemainingEvents()
+        }
+    }
+
+    @Test
+    fun `a sender the room member list knows nothing about keeps the profile the timeline gave`() = runTest {
+        val factory = aTimelineItemsFactory(
+            config = TimelineItemsFactoryConfig(
+                computeReadReceipts = false,
+                computeReactions = false,
+            )
+        )
+        val items = listOf(
+            MatrixTimelineItem.Event(
+                uniqueId = UniqueId("event-0"),
+                event = anEventTimelineItem(
+                    sender = A_USER_ID,
+                    senderProfile = ProfileDetails.Unavailable,
+                    content = aMessageContent(body = "A regular message"),
+                ),
+            ),
+        )
+        factory.timelineItems.test {
+            factory.replaceWith(
+                timelineItems = items,
+                roomMembers = listOf(aRoomMember(userId = A_USER_ID_2, displayName = "Bob")),
+                renderReadReceipts = false,
+            )
+            val event = awaitItem().filterIsInstance<TimelineItem.Event>().single()
+            assertThat(event.senderProfile).isEqualTo(ProfileDetails.Unavailable)
+            cancelAndIgnoreRemainingEvents()
+        }
+    }
+
     private suspend fun TestScope.groupPositionsOf(timestamps: List<Long>): List<TimelineItemGroupPosition> {
         val factory = aTimelineItemsFactory(
             config = TimelineItemsFactoryConfig(