diff --git a/core/src/com/unciv/ui/images/Portrait.kt b/core/src/com/unciv/ui/images/Portrait.kt
index bdc9dff407..6980bad505 100644
--- a/core/src/com/unciv/ui/images/Portrait.kt
+++ b/core/src/com/unciv/ui/images/Portrait.kt
@@ -171,6 +171,12 @@ class PortraitBuilding(name: String, size: Float) : Portrait(Type.Building, name
     }
 }
 
+class PortraitUnavailableWonderForTechTree(name: String, size: Float) : Portrait(Type.Building, name, size) {
+    override fun getDefaultOuterBackgroundTint(): Color {
+        return Color.RED
+    }
+}
+
 class PortraitUnique(name: String, size: Float) : Portrait(Type.Unique, name, size) {
     override fun getDefaultImageTint(): Color {
         return Color.BLACK
diff --git a/core/src/com/unciv/ui/objectdescriptions/TechnologyDescriptions.kt b/core/src/com/unciv/ui/objectdescriptions/TechnologyDescriptions.kt
index f99e8b78ce..e460d10319 100644
--- a/core/src/com/unciv/ui/objectdescriptions/TechnologyDescriptions.kt
+++ b/core/src/com/unciv/ui/objectdescriptions/TechnologyDescriptions.kt
@@ -15,6 +15,7 @@ import com.unciv.models.translations.tr
 import com.unciv.ui.components.Fonts
 import com.unciv.ui.components.extensions.center
 import com.unciv.ui.images.ImageGetter
+import com.unciv.ui.images.PortraitUnavailableWonderForTechTree
 import com.unciv.ui.screens.civilopediascreen.FormattedLine
 import com.unciv.ui.screens.civilopediascreen.ICivilopediaText
 import com.unciv.ui.screens.pickerscreens.TechButton
@@ -91,7 +92,24 @@ object TechnologyDescriptions {
         }
 
         for (building in getEnabledBuildings(techName, ruleset, viewingCiv)) {
-            yield(ImageGetter.getConstructionPortrait(building.name, techIconSize))
+            // We don't need to show the unavailable marker for techs that are already researched
+            // since this is mostly a feature to choose which technologies to research.
+            if (building.isWonder && !viewingCiv.tech.isResearched(techName)) {
+                val isAlreadyBuilt = viewingCiv.gameInfo.getCities()
+                    // This is theoretically not necessary since we already checked the viewingCiv
+                    // doesn't have the tech, so it can't have this built anyways. It should be a
+                    // little more performant though to add this filter.
+                    .filter{ it.civ != viewingCiv }
+                    .any { it.cityConstructions.builtBuildings.contains(building.name) }
+                val wonderConstructionPortrait =
+                        if (isAlreadyBuilt)
+                            PortraitUnavailableWonderForTechTree(building.name, techIconSize)
+                        else
+                            ImageGetter.getConstructionPortrait(building.name, techIconSize)
+                yield(wonderConstructionPortrait)
+            } else {
+                yield(ImageGetter.getConstructionPortrait(building.name, techIconSize))
+            }
         }
 
         yieldAll(