diff --git a/spring-cloud-stream/src/main/java/org/springframework/cloud/stream/function/FunctionConfiguration.java b/spring-cloud-stream/src/main/java/org/springframework/cloud/stream/function/FunctionConfiguration.java
index 1e84264e7..e33403a04 100644
--- a/spring-cloud-stream/src/main/java/org/springframework/cloud/stream/function/FunctionConfiguration.java
+++ b/spring-cloud-stream/src/main/java/org/springframework/cloud/stream/function/FunctionConfiguration.java
@@ -363,6 +363,13 @@ public class FunctionConfiguration {
 
 			if (isReactiveOrMultipleInputOutput(bindableProxyFactory, functionType)) {
 				Publisher[] inputPublishers = inputBindingNames.stream().map(inputBindingName -> {
+					BindingProperties bindingProperties = this.serviceProperties.getBindings().get(inputBindingName);
+					ConsumerProperties consumerProperties = bindingProperties == null ? null : bindingProperties.getConsumer();
+					if (consumerProperties != null) {
+						Assert.isTrue(consumerProperties.getConcurrency() <= 1, "Concurrency > 1 is not supported by reactive "
+								+ "consumer, given that project reactor maintains its own concurrency mechanism. Was '..."
+								+ inputBindingName + ".consumer.concurrency=" + consumerProperties.getConcurrency() + "'");
+					}
 					SubscribableChannel inputChannel = this.applicationContext.getBean(inputBindingName, SubscribableChannel.class);
 					return IntegrationReactiveUtils.messageChannelToFlux(inputChannel);
 				}).toArray(Publisher[]::new);
diff --git a/spring-cloud-stream/src/test/java/org/springframework/cloud/stream/function/ImplicitFunctionBindingTests.java b/spring-cloud-stream/src/test/java/org/springframework/cloud/stream/function/ImplicitFunctionBindingTests.java
index 0481926a6..786a14518 100644
--- a/spring-cloud-stream/src/test/java/org/springframework/cloud/stream/function/ImplicitFunctionBindingTests.java
+++ b/spring-cloud-stream/src/test/java/org/springframework/cloud/stream/function/ImplicitFunctionBindingTests.java
@@ -32,6 +32,7 @@ import org.junit.Test;
 import reactor.core.publisher.Flux;
 import reactor.core.publisher.Mono;
 
+import org.springframework.beans.factory.BeanCreationException;
 import org.springframework.boot.WebApplicationType;
 import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
 import org.springframework.boot.builder.SpringApplicationBuilder;
@@ -758,6 +759,22 @@ public class ImplicitFunctionBindingTests {
 		}
 	}
 
+	@Test(expected = BeanCreationException.class)
+	public void testReactiveConsumerWithConcurrencyFailureConfiguration() {
+		System.clearProperty("spring.cloud.function.definition");
+		new SpringApplicationBuilder(
+				TestChannelBinderConfiguration.getCompleteConfiguration(ReactiveConsumerWithConcurrencyFailureConfiguration.class))
+						.web(WebApplicationType.NONE).run("--spring.jmx.enabled=false",
+								"--spring.cloud.stream.bindings.input-in-0.consumer.concurrency=2");
+	}
+
+	@EnableAutoConfiguration
+	public static class ReactiveConsumerWithConcurrencyFailureConfiguration {
+		@Bean
+		public Consumer<Flux<Message<String>>> input() {
+			return flux -> flux.subscribe(System.out::println);
+		}
+	}
 
 	@EnableAutoConfiguration
 	public static class NoEnableBindingConfiguration {