diff --git a/SystemExtensions/Collections/CircularQueue.cs b/SystemExtensions/Collections/CircularQueue.cs
new file mode 100644
index 0000000..2289a83
--- /dev/null
+++ b/SystemExtensions/Collections/CircularQueue.cs
@@ -0,0 +1,97 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace SystemExtensions.Collections
+{
+    /// <summary>
+    /// Implementation of a queue based on a circular array. Efficient implementation when capacity is known from before.
+    /// </summary>
+    /// <typeparam name="T">Provided type.</typeparam>
+    class CircularQueue<T> : IQueue<T>
+    {
+        #region Fields
+        int count;
+        int capacity;
+        int insertLocation;
+        int readLocation;
+        T[] items;
+        #endregion
+        #region Properties
+        /// <summary>
+        /// Returns the number of items in the queue.
+        /// </summary>
+        public int Count { get => count; }
+        /// <summary>
+        /// Capacity of the queue.
+        /// </summary>
+        public int Capacity { get => capacity;
+            set
+            {
+
+            }
+        }
+        #endregion
+        #region Constructors
+        public CircularQueue()
+        {
+            count = 0;
+            capacity = 10;
+            items = new T[capacity];
+        }
+        public CircularQueue(int capacity)
+        {
+            this.capacity = capacity;
+            count = 0;
+            items = new T[capacity];
+        }
+        #endregion
+        #region Public Methods
+        /// <summary>
+        /// Clears the queue.
+        /// </summary>
+        public void Clear()
+        {
+            throw new NotImplementedException();
+        }
+        /// <summary>
+        /// Checks if provided item is present into the queue.
+        /// </summary>
+        /// <param name="item">Item to be checked.</param>
+        /// <returns>True if item is present. False otherwise.</returns>
+        public bool Contains(T item)
+        {
+            throw new NotImplementedException();
+        }
+        /// <summary>
+        /// Removes and returns the first item from the queue.
+        /// </summary>
+        /// <returns>First item from the queue.</returns>
+        public T Dequeue()
+        {
+            throw new NotImplementedException();
+        }
+        /// <summary>
+        /// Inserts provided item into the queue.
+        /// </summary>
+        /// <param name="item">Item to be inserted.</param>
+        public void Enqueue(T item)
+        {
+            throw new NotImplementedException();
+        }
+        /// <summary>
+        /// Checks and returns the first item from the queue without removing it.
+        /// </summary>
+        /// <returns>The first item from the queue.</returns>
+        public T Peek()
+        {
+            throw new NotImplementedException();
+        }
+
+        #endregion
+        #region Private Methods
+        #endregion
+    }
+}
diff --git a/SystemExtensions/Collections/IQueue.cs b/SystemExtensions/Collections/IQueue.cs
new file mode 100644
index 0000000..bbe5515
--- /dev/null
+++ b/SystemExtensions/Collections/IQueue.cs
@@ -0,0 +1,45 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace SystemExtensions.Collections
+{
+    /// <summary>
+    /// Interface for queue implementations.
+    /// </summary>
+    /// <typeparam name="T">Provided type.</typeparam>
+    public interface IQueue<T>
+    {
+        /// <summary>
+        /// Returns the number of items in the queue.
+        /// </summary>
+        int Count { get; }
+        /// <summary>
+        /// Inserts item into the queue.
+        /// </summary>
+        /// <param name="item">Item to be inserted.</param>
+        void Enqueue(T item);
+        /// <summary>
+        /// Remove the first item in the queue.
+        /// </summary>
+        /// <returns>First item in the queue.</returns>
+        T Dequeue();
+        /// <summary>
+        /// Looks up the first item from the queue without removing it.
+        /// </summary>
+        /// <returns>First item from the queue.</returns>
+        T Peek();
+        /// <summary>
+        /// Clears the contents of the queue.
+        /// </summary>
+        void Clear();
+        /// <summary>
+        /// Checks if queue contains an item.
+        /// </summary>
+        /// <param name="item">Item to be checked.</param>
+        /// <returns>True if queue contains provided item. False otherwise.</returns>
+        bool Contains(T item);
+    }
+}
diff --git a/SystemExtensions/Collections/PriorityQueue.cs b/SystemExtensions/Collections/PriorityQueue.cs
index b5b49ff..38525ab 100644
--- a/SystemExtensions/Collections/PriorityQueue.cs
+++ b/SystemExtensions/Collections/PriorityQueue.cs
@@ -11,7 +11,7 @@ namespace SystemExtensions.Collections
     /// Exposes some of the functionality of the Binary Heap as a queue.
     /// </summary>
     /// <typeparam name="T">Provided type.</typeparam>
-    public class PriorityQueue<T>
+    public class PriorityQueue<T> : IQueue<T>
     {
         #region Fields
         private BinaryHeap<T> binaryHeap;
@@ -77,6 +77,15 @@ namespace SystemExtensions.Collections
         {
             binaryHeap.Clear();
         }
+        /// <summary>
+        /// Checks if queue contains provided item.
+        /// </summary>
+        /// <param name="item">Item to be checked.</param>
+        /// <returns>True if queue contains the provided item. False otherwise.</returns>
+        public bool Contains(T item)
+        {
+            return binaryHeap.Contains(item);
+        }
         #endregion
         #region Private Methods
         #endregion
diff --git a/SystemExtensions/SystemExtensions.csproj b/SystemExtensions/SystemExtensions.csproj
index 409f245..f2c6cca 100644
--- a/SystemExtensions/SystemExtensions.csproj
+++ b/SystemExtensions/SystemExtensions.csproj
@@ -46,12 +46,15 @@
   </ItemGroup>
   <ItemGroup>
     <Compile Include="Collections\BinaryHeap.cs" />
+    <Compile Include="Collections\CircularQueue.cs" />
     <Compile Include="Collections\FibonacciHeap.cs" />
+    <Compile Include="Collections\IQueue.cs" />
     <Compile Include="Collections\PriorityQueue.cs" />
     <Compile Include="Collections\Treap.cs" />
     <Compile Include="Comparators.cs" />
     <Compile Include="Properties\AssemblyInfo.cs" />
     <Compile Include="Threading\PriorityThreadPool.cs" />
   </ItemGroup>
+  <ItemGroup />
   <Import Project="$(MSBuildToolsPath)\Microsoft.CSharp.targets" />
 </Project>
\ No newline at end of file