diff --git a/src/cargotype.h b/src/cargotype.h
index b2b6f70190..c36aa3afcb 100644
--- a/src/cargotype.h
+++ b/src/cargotype.h
@@ -168,7 +168,6 @@ struct CargoSpec {
 		};
 
 		bool operator==(const Iterator &other) const { return this->index == other.index; }
-		bool operator!=(const Iterator &other) const { return !(*this == other); }
 		CargoSpec * operator*() const { return CargoSpec::Get(this->index); }
 		Iterator & operator++() { this->index++; this->ValidateIndex(); return *this; }
 
diff --git a/src/core/bitmath_func.hpp b/src/core/bitmath_func.hpp
index befcb1d45c..ed4461e2c1 100644
--- a/src/core/bitmath_func.hpp
+++ b/src/core/bitmath_func.hpp
@@ -315,7 +315,6 @@ struct SetBitIterator {
 		{
 			return this->bitset == other.bitset;
 		}
-		bool operator!=(const Iterator &other) const { return !(*this == other); }
 		Tbitpos operator*() const { return this->bitpos; }
 		Iterator & operator++() { this->Next(); this->Validate(); return *this; }
 
diff --git a/src/core/pool_type.hpp b/src/core/pool_type.hpp
index b4c7cdb794..5cb69fa3c4 100644
--- a/src/core/pool_type.hpp
+++ b/src/core/pool_type.hpp
@@ -162,7 +162,6 @@ public:
 		};
 
 		bool operator==(const PoolIterator &other) const { return this->index == other.index; }
-		bool operator!=(const PoolIterator &other) const { return !(*this == other); }
 		T * operator*() const { return T::Get(this->index); }
 		PoolIterator & operator++() { this->index++; this->ValidateIndex(); return *this; }
 
@@ -206,7 +205,6 @@ public:
 		};
 
 		bool operator==(const PoolIteratorFiltered &other) const { return this->index == other.index; }
-		bool operator!=(const PoolIteratorFiltered &other) const { return !(*this == other); }
 		T * operator*() const { return T::Get(this->index); }
 		PoolIteratorFiltered & operator++() { this->index++; this->ValidateIndex(); return *this; }
 
diff --git a/src/fios.cpp b/src/fios.cpp
index 0cdae26f71..cdb653a338 100644
--- a/src/fios.cpp
+++ b/src/fios.cpp
@@ -618,11 +618,6 @@ struct ScenarioIdentifier {
 	{
 		return this->scenid == other.scenid && this->md5sum == other.md5sum;
 	}
-
-	bool operator != (const ScenarioIdentifier &other) const
-	{
-		return !(*this == other);
-	}
 };
 
 /**
diff --git a/src/map_func.h b/src/map_func.h
index 45a5a3ee98..9f34cb835b 100644
--- a/src/map_func.h
+++ b/src/map_func.h
@@ -217,7 +217,6 @@ private:
 
 		explicit Iterator(TileIndex index) : index(index) {}
 		bool operator==(const Iterator &other) const { return this->index == other.index; }
-		bool operator!=(const Iterator &other) const { return !(*this == other); }
 		Tile operator*() const { return this->index; }
 		Iterator & operator++() { this->index++; return *this; }
 	private:
diff --git a/src/order_type.h b/src/order_type.h
index 2701b029fe..8df0889af0 100644
--- a/src/order_type.h
+++ b/src/order_type.h
@@ -30,14 +30,9 @@ struct DestinationID {
 	constexpr BaseType base() const noexcept { return this->value; }
 
 	constexpr bool operator ==(const DestinationID &destination) const { return this->value == destination.value; }
-	constexpr bool operator !=(const DestinationID &destination) const { return this->value != destination.value; }
 	constexpr bool operator ==(const StationID &station) const { return this->value == station; }
-	constexpr bool operator !=(const StationID &station) const { return this->value != station; }
 };
 
-constexpr bool operator ==(const StationID &station, const DestinationID &destination) { return destination == station; }
-constexpr bool operator !=(const StationID &station, const DestinationID &destination) { return destination != station; }
-
 /** Invalid vehicle order index (sentinel) */
 static const VehicleOrderID INVALID_VEH_ORDER_ID = 0xFF;
 /** Last valid VehicleOrderID. */
diff --git a/src/pathfinder/water_regions.h b/src/pathfinder/water_regions.h
index bc278dd2aa..9364b2e1eb 100644
--- a/src/pathfinder/water_regions.h
+++ b/src/pathfinder/water_regions.h
@@ -30,7 +30,6 @@ struct WaterRegionPatchDesc
 	TWaterRegionPatchLabel label; ///< Unique label identifying the patch within the region
 
 	bool operator==(const WaterRegionPatchDesc &other) const { return x == other.x && y == other.y && label == other.label; }
-	bool operator!=(const WaterRegionPatchDesc &other) const { return !(*this == other); }
 };
 
 
@@ -46,7 +45,6 @@ struct WaterRegionDesc
 	WaterRegionDesc(const WaterRegionPatchDesc &water_region_patch) : x(water_region_patch.x), y(water_region_patch.y) {}
 
 	bool operator==(const WaterRegionDesc &other) const { return x == other.x && y == other.y; }
-	bool operator!=(const WaterRegionDesc &other) const { return !(*this == other); }
 };
 
 int CalculateWaterRegionPatchHash(const WaterRegionPatchDesc &water_region_patch);
diff --git a/src/tilearea_type.h b/src/tilearea_type.h
index 2f7f4e0f20..9add7cfe8b 100644
--- a/src/tilearea_type.h
+++ b/src/tilearea_type.h
@@ -152,13 +152,6 @@ public:
 	{
 		return this->tile == rhs.tile;
 	}
-	/**
-	 * Inequality comparison.
-	 */
-	bool operator !=(const TileIterator &rhs) const
-	{
-		return this->tile != rhs.tile;
-	}
 
 	/**
 	 * Equality comparison.
@@ -167,13 +160,6 @@ public:
 	{
 		return this->tile == rhs;
 	}
-	/**
-	 * Inequality comparison.
-	 */
-	bool operator !=(const TileIndex &rhs) const
-	{
-		return this->tile != rhs;
-	}
 
 	static std::unique_ptr<TileIterator> Create(TileIndex corner1, TileIndex corner2, bool diagonal);
 };
diff --git a/src/train_gui.cpp b/src/train_gui.cpp
index 3c8734f131..8ed12f9c22 100644
--- a/src/train_gui.cpp
+++ b/src/train_gui.cpp
@@ -179,12 +179,6 @@ struct CargoSummaryItem {
 	uint amount;      ///< Amount that is carried
 	StationID source; ///< One of the source stations
 
-	/** Used by CargoSummary::Find() and similar functions */
-	inline bool operator != (const CargoSummaryItem &other) const
-	{
-		return this->cargo != other.cargo || this->subtype != other.subtype;
-	}
-
 	/** Used by std::find() and similar functions */
 	inline bool operator == (const CargoSummaryItem &other) const
 	{
diff --git a/src/vehicle_base.h b/src/vehicle_base.h
index 1aa29bbd2b..52a82cb594 100644
--- a/src/vehicle_base.h
+++ b/src/vehicle_base.h
@@ -141,11 +141,6 @@ struct VehicleSpriteSeq {
 		return this->count == other.count && MemCmpT<PalSpriteID>(this->seq, other.seq, this->count) == 0;
 	}
 
-	bool operator!=(const VehicleSpriteSeq &other) const
-	{
-		return !this->operator==(other);
-	}
-
 	/**
 	 * Check whether the sequence contains any sprites.
 	 */
@@ -1050,7 +1045,6 @@ public:
 		}
 
 		bool operator==(const OrderIterator &other) const { return this->order == other.order; }
-		bool operator!=(const OrderIterator &other) const { return !(*this == other); }
 		Order * operator*() const { return this->order; }
 		OrderIterator & operator++()
 		{
diff --git a/src/vehicle_gui.cpp b/src/vehicle_gui.cpp
index d68f422971..b9509eb170 100644
--- a/src/vehicle_gui.cpp
+++ b/src/vehicle_gui.cpp
@@ -665,16 +665,6 @@ struct RefitOption {
 	uint8_t subtype;     ///< Subcargo to use
 	StringID string;  ///< GRF-local String to display for the cargo
 
-	/**
-	 * Inequality operator for #RefitOption.
-	 * @param other Compare to this #RefitOption.
-	 * @return True if both #RefitOption are different.
-	 */
-	inline bool operator != (const RefitOption &other) const
-	{
-		return other.cargo != this->cargo || other.string != this->string;
-	}
-
 	/**
 	 * Equality operator for #RefitOption.
 	 * @param other Compare to this #RefitOption.
diff --git a/src/window_gui.h b/src/window_gui.h
index a024a09029..0d2810a53e 100644
--- a/src/window_gui.h
+++ b/src/window_gui.h
@@ -872,7 +872,6 @@ public:
 		explicit WindowIterator(const Window *w) : it(w->z_position) {}
 
 		bool operator==(const WindowIterator &other) const { return this->it == other.it; }
-		bool operator!=(const WindowIterator &other) const { return !(*this == other); }
 		Window * operator*() const { return *this->it; }
 		WindowIterator & operator++() { this->Next(); this->Validate(); return *this; }