diff --git a/streams/src/main/java/org/apache/kafka/streams/state/internals/CachingKeyValueStore.java b/streams/src/main/java/org/apache/kafka/streams/state/internals/CachingKeyValueStore.java
index f0669a4..c0574df 100644
--- a/streams/src/main/java/org/apache/kafka/streams/state/internals/CachingKeyValueStore.java
+++ b/streams/src/main/java/org/apache/kafka/streams/state/internals/CachingKeyValueStore.java
@@ -31,6 +31,9 @@ import org.apache.kafka.streams.state.StateSerdes;
 
 import java.util.List;
 import java.util.Objects;
+import java.util.concurrent.locks.Lock;
+import java.util.concurrent.locks.ReadWriteLock;
+import java.util.concurrent.locks.ReentrantReadWriteLock;
 
 class CachingKeyValueStore<K, V> extends WrappedStateStore.AbstractStateStore implements KeyValueStore<Bytes, byte[]>, CachedStateStore<K, V> {
 
@@ -44,6 +47,7 @@ class CachingKeyValueStore<K, V> extends WrappedStateStore.AbstractStateStore im
     private InternalProcessorContext context;
     private StateSerdes<K, V> serdes;
     private Thread streamThread;
+    private ReadWriteLock lock = new ReentrantReadWriteLock();
 
     CachingKeyValueStore(final KeyValueStore<Bytes, byte[]> underlying,
                          final Serde<K> keySerde,
@@ -108,9 +112,14 @@ class CachingKeyValueStore<K, V> extends WrappedStateStore.AbstractStateStore im
     }
 
     @Override
-    public synchronized void flush() {
-        cache.flush(cacheName);
-        underlying.flush();
+    public void flush() {
+        lock.writeLock().lock();
+        try {
+            cache.flush(cacheName);
+            underlying.flush();
+        } finally {
+            lock.writeLock().unlock();
+        }
     }
 
     @Override
@@ -131,10 +140,21 @@ class CachingKeyValueStore<K, V> extends WrappedStateStore.AbstractStateStore im
     }
 
     @Override
-    public synchronized byte[] get(final Bytes key) {
+    public byte[] get(final Bytes key) {
         validateStoreOpen();
-        Objects.requireNonNull(key);
-        return getInternal(key);
+        Lock theLock;
+        if (Thread.currentThread().equals(streamThread)) {
+            theLock = lock.writeLock();
+        } else {
+            theLock = lock.readLock();
+        }
+        theLock.lock();
+        try {
+            Objects.requireNonNull(key);
+            return getInternal(key);
+        } finally {
+            theLock.unlock();
+        }
     }
 
     private byte[] getInternal(final Bytes key) {
@@ -176,50 +196,80 @@ class CachingKeyValueStore<K, V> extends WrappedStateStore.AbstractStateStore im
     }
 
     @Override
-    public synchronized long approximateNumEntries() {
-        validateStoreOpen();
-        return underlying.approximateNumEntries();
+    public long approximateNumEntries() {
+        lock.readLock().lock();
+        try {
+            validateStoreOpen();
+            return underlying.approximateNumEntries();
+        } finally {
+            lock.readLock().unlock();
+        }
     }
 
     @Override
     public synchronized void put(final Bytes key, final byte[] value) {
         Objects.requireNonNull(key, "key cannot be null");
-        validateStoreOpen();
-        putInternal(key, value);
+        lock.writeLock().lock();
+        try {
+            validateStoreOpen();
+            putInternal(key, value);
+        } finally {
+            lock.writeLock().unlock();
+        }
     }
 
     private synchronized void putInternal(final Bytes rawKey, final byte[] value) {
         Objects.requireNonNull(rawKey, "key cannot be null");
-        cache.put(cacheName, rawKey, new LRUCacheEntry(value, true, context.offset(),
+        lock.writeLock().lock();
+        try {
+            cache.put(cacheName, rawKey, new LRUCacheEntry(value, true, context.offset(),
                   context.timestamp(), context.partition(), context.topic()));
+        } finally {
+            lock.writeLock().unlock();
+        }
     }
 
     @Override
     public synchronized byte[] putIfAbsent(final Bytes key, final byte[] value) {
         Objects.requireNonNull(key, "key cannot be null");
         validateStoreOpen();
-        final byte[] v = getInternal(key);
-        if (v == null) {
-            putInternal(key, value);
+        lock.writeLock().lock();
+        try {
+            final byte[] v = getInternal(key);
+            if (v == null) {
+                putInternal(key, value);
+            }
+            return v;
+        } finally {
+            lock.writeLock().unlock();
         }
-        return v;
     }
 
     @Override
     public synchronized void putAll(final List<KeyValue<Bytes, byte[]>> entries) {
-        for (KeyValue<Bytes, byte[]> entry : entries) {
-            put(entry.key, entry.value);
+        lock.writeLock().lock();
+        try {
+            for (KeyValue<Bytes, byte[]> entry : entries) {
+                put(entry.key, entry.value);
+            }
+        } finally {
+            lock.writeLock().unlock();
         }
     }
 
     @Override
     public synchronized byte[] delete(final Bytes key) {
         validateStoreOpen();
-        Objects.requireNonNull(key);
-        final byte[] v = getInternal(key);
-        cache.delete(cacheName, key);
-        underlying.delete(key);
-        return v;
+        lock.writeLock().lock();
+        try {
+            Objects.requireNonNull(key);
+            final byte[] v = getInternal(key);
+            cache.delete(cacheName, key);
+            underlying.delete(key);
+            return v;
+        } finally {
+            lock.writeLock().unlock();
+        }
     }
 
     KeyValueStore<Bytes, byte[]> underlying() {