diff --git a/docs/developer-guide/ksqldb-reference/scalar-functions.md b/docs/developer-guide/ksqldb-reference/scalar-functions.md
index 831fc9aeca80..c937505cccd8 100644
--- a/docs/developer-guide/ksqldb-reference/scalar-functions.md
+++ b/docs/developer-guide/ksqldb-reference/scalar-functions.md
@@ -481,6 +481,16 @@ the entire substring is returned by default.
 For example, `REGEXP_EXTRACT("(\\w+) (\\w+)", 'hello there nice day', 2)`
 returns `['there', 'day']`.
 
+### `REGEXP_REPLACE`
+
+```sql
+REGEXP_REPLACE(col1, 'a.b+', 'bar')
+```
+
+Replace all matches of a regex in an input string with a new string.
+If either the input string, regular expression, or new string is null,
+the result is null.
+
 ### `REGEXP_SPLIT_TO_ARRAY`
 
 ```sql
diff --git a/ksqldb-engine/src/main/java/io/confluent/ksql/function/udf/string/RegexpReplace.java b/ksqldb-engine/src/main/java/io/confluent/ksql/function/udf/string/RegexpReplace.java
new file mode 100644
index 000000000000..775a5c530e18
--- /dev/null
+++ b/ksqldb-engine/src/main/java/io/confluent/ksql/function/udf/string/RegexpReplace.java
@@ -0,0 +1,50 @@
+/*
+ * Copyright 2020 Confluent Inc.
+ *
+ * Licensed under the Confluent Community License (the "License"); you may not use
+ * this file except in compliance with the License.  You may obtain a copy of the
+ * License at
+ *
+ * http://www.confluent.io/confluent-community-license
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OF ANY KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations under the License.
+ */
+
+package io.confluent.ksql.function.udf.string;
+
+import io.confluent.ksql.function.KsqlFunctionException;
+import io.confluent.ksql.function.udf.Udf;
+import io.confluent.ksql.function.udf.UdfDescription;
+import io.confluent.ksql.function.udf.UdfParameter;
+import io.confluent.ksql.util.KsqlConstants;
+import java.util.regex.PatternSyntaxException;
+
+@UdfDescription(name = "regexp_replace",
+    author = KsqlConstants.CONFLUENT_AUTHOR,
+    description = "Replaces all matches of a regexp in a string with a new substring.")
+public class RegexpReplace {
+
+  @Udf(description = "Returns a new string with all matches of regexp in str replaced with newStr")
+  public String regexpReplace(
+      @UdfParameter(
+          description = "The source string. If null, then function returns null.") final String str,
+      @UdfParameter(
+          description = "The regexp to match."
+              + " If null, then function returns null.") final String regexp,
+      @UdfParameter(
+          description = "The string to replace the matches with."
+              + " If null, then function returns null.") final String newStr) {
+    if (str == null || regexp == null || newStr == null) {
+      return null;
+    }
+
+    try {
+      return str.replaceAll(regexp, newStr);
+    } catch (PatternSyntaxException e) {
+      throw new KsqlFunctionException("Invalid regular expression pattern: " + regexp, e);
+    }
+  }
+}
diff --git a/ksqldb-engine/src/test/java/io/confluent/ksql/function/udf/string/RegexpReplaceTest.java b/ksqldb-engine/src/test/java/io/confluent/ksql/function/udf/string/RegexpReplaceTest.java
new file mode 100644
index 000000000000..77b37c2c2fd5
--- /dev/null
+++ b/ksqldb-engine/src/test/java/io/confluent/ksql/function/udf/string/RegexpReplaceTest.java
@@ -0,0 +1,55 @@
+/*
+ * Copyright 2020 Confluent Inc.
+ *
+ * Licensed under the Confluent Community License (the "License"); you may not use
+ * this file except in compliance with the License.  You may obtain a copy of the
+ * License at
+ *
+ * http://www.confluent.io/confluent-community-license
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OF ANY KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations under the License.
+ */
+
+package io.confluent.ksql.function.udf.string;
+
+import static org.hamcrest.MatcherAssert.assertThat;
+import static org.hamcrest.Matchers.is;
+import static org.hamcrest.Matchers.isEmptyOrNullString;
+
+import io.confluent.ksql.function.KsqlFunctionException;
+import org.junit.Test;
+
+public class RegexpReplaceTest {
+
+  private RegexpReplace udf = new RegexpReplace();
+
+  @Test
+  public void shouldHandleNull() {
+    assertThat(udf.regexpReplace(null, "foo", "bar"), isEmptyOrNullString());
+    assertThat(udf.regexpReplace("foo", null, "bar"), isEmptyOrNullString());
+    assertThat(udf.regexpReplace("foo", "bar", null), isEmptyOrNullString());
+  }
+
+  @Test
+  public void shouldReplace() {
+    assertThat(udf.regexpReplace("foobar", "foo", "bar"), is("barbar"));
+    assertThat(udf.regexpReplace("foobar", "fooo", "bar"), is("foobar"));
+    assertThat(udf.regexpReplace("foobar", "o", ""), is("fbar"));
+    assertThat(udf.regexpReplace("abc", "", "n"), is("nanbncn"));
+
+    assertThat(udf.regexpReplace("foobar", "(foo|bar)", "cat"), is("catcat"));
+    assertThat(udf.regexpReplace("foobar", "^foo", "cat"), is("catbar"));
+    assertThat(udf.regexpReplace("foobar", "^bar", "cat"), is("foobar"));
+    assertThat(udf.regexpReplace("barbar", "bar$", "cat"), is("barcat"));
+    assertThat(udf.regexpReplace("aababa", "ab", "xy"), is("axyxya"));
+    assertThat(udf.regexpReplace("aababa", "(ab)+", "xy"), is("axya"));
+  }
+
+  @Test(expected = KsqlFunctionException.class)
+  public void shouldThrowExceptionOnBadPattern() {
+    udf.regexpReplace("foobar", "(()", "bar");
+  }
+}
diff --git a/ksqldb-functional-tests/src/test/resources/historical_plans/replace_-_regexp_replace/6.0.0_1591049420147/plan.json b/ksqldb-functional-tests/src/test/resources/historical_plans/replace_-_regexp_replace/6.0.0_1591049420147/plan.json
new file mode 100644
index 000000000000..d2c5687ea650
--- /dev/null
+++ b/ksqldb-functional-tests/src/test/resources/historical_plans/replace_-_regexp_replace/6.0.0_1591049420147/plan.json
@@ -0,0 +1,126 @@
+{
+  "plan" : [ {
+    "@type" : "ksqlPlanV1",
+    "statementText" : "CREATE STREAM TEST (K STRING KEY, INPUT_STRING STRING, PATTERN STRING) WITH (KAFKA_TOPIC='test_topic', VALUE_FORMAT='JSON');",
+    "ddlCommand" : {
+      "@type" : "createStreamV1",
+      "sourceName" : "TEST",
+      "schema" : "`K` STRING KEY, `INPUT_STRING` STRING, `PATTERN` STRING",
+      "topicName" : "test_topic",
+      "formats" : {
+        "keyFormat" : {
+          "format" : "KAFKA"
+        },
+        "valueFormat" : {
+          "format" : "JSON"
+        }
+      }
+    }
+  }, {
+    "@type" : "ksqlPlanV1",
+    "statementText" : "CREATE STREAM OUTPUT AS SELECT\n  TEST.K K,\n  REGEXP_REPLACE(TEST.INPUT_STRING, TEST.PATTERN, 'cat') EXTRACTED\nFROM TEST TEST\nEMIT CHANGES",
+    "ddlCommand" : {
+      "@type" : "createStreamV1",
+      "sourceName" : "OUTPUT",
+      "schema" : "`K` STRING KEY, `EXTRACTED` STRING",
+      "topicName" : "OUTPUT",
+      "formats" : {
+        "keyFormat" : {
+          "format" : "KAFKA"
+        },
+        "valueFormat" : {
+          "format" : "JSON"
+        }
+      }
+    },
+    "queryPlan" : {
+      "sources" : [ "TEST" ],
+      "sink" : "OUTPUT",
+      "physicalPlan" : {
+        "@type" : "streamSinkV1",
+        "properties" : {
+          "queryContext" : "OUTPUT"
+        },
+        "source" : {
+          "@type" : "streamSelectV1",
+          "properties" : {
+            "queryContext" : "Project"
+          },
+          "source" : {
+            "@type" : "streamSourceV1",
+            "properties" : {
+              "queryContext" : "KsqlTopic/Source"
+            },
+            "topicName" : "test_topic",
+            "formats" : {
+              "keyFormat" : {
+                "format" : "KAFKA"
+              },
+              "valueFormat" : {
+                "format" : "JSON"
+              }
+            },
+            "sourceSchema" : "`K` STRING KEY, `INPUT_STRING` STRING, `PATTERN` STRING"
+          },
+          "keyColumnNames" : [ "K" ],
+          "selectExpressions" : [ "REGEXP_REPLACE(INPUT_STRING, PATTERN, 'cat') AS EXTRACTED" ]
+        },
+        "formats" : {
+          "keyFormat" : {
+            "format" : "KAFKA"
+          },
+          "valueFormat" : {
+            "format" : "JSON"
+          }
+        },
+        "topicName" : "OUTPUT"
+      },
+      "queryId" : "CSAS_OUTPUT_0"
+    }
+  } ],
+  "configs" : {
+    "ksql.extension.dir" : "ext",
+    "ksql.streams.cache.max.bytes.buffering" : "0",
+    "ksql.security.extension.class" : null,
+    "ksql.transient.prefix" : "transient_",
+    "ksql.persistence.wrap.single.values" : "true",
+    "ksql.authorization.cache.expiry.time.secs" : "30",
+    "ksql.schema.registry.url" : "",
+    "ksql.streams.default.deserialization.exception.handler" : "io.confluent.ksql.errors.LogMetricAndContinueExceptionHandler",
+    "ksql.output.topic.name.prefix" : "",
+    "ksql.streams.auto.offset.reset" : "earliest",
+    "ksql.query.pull.enable.standby.reads" : "false",
+    "ksql.connect.url" : "http://localhost:8083",
+    "ksql.service.id" : "some.ksql.service.id",
+    "ksql.internal.topic.min.insync.replicas" : "1",
+    "ksql.streams.shutdown.timeout.ms" : "300000",
+    "ksql.internal.topic.replicas" : "1",
+    "ksql.insert.into.values.enabled" : "true",
+    "ksql.query.pull.max.allowed.offset.lag" : "9223372036854775807",
+    "ksql.query.pull.max.qps" : "2147483647",
+    "ksql.streams.default.production.exception.handler" : "io.confluent.ksql.errors.ProductionExceptionHandlerUtil$LogAndFailProductionExceptionHandler",
+    "ksql.access.validator.enable" : "auto",
+    "ksql.streams.bootstrap.servers" : "localhost:0",
+    "ksql.streams.commit.interval.ms" : "2000",
+    "ksql.metric.reporters" : "",
+    "ksql.query.pull.metrics.enabled" : "false",
+    "ksql.streams.auto.commit.interval.ms" : "0",
+    "ksql.metrics.extension" : null,
+    "ksql.streams.topology.optimization" : "all",
+    "ksql.hidden.topics" : "_confluent.*,__confluent.*,_schemas,__consumer_offsets,__transaction_state,connect-configs,connect-offsets,connect-status,connect-statuses",
+    "ksql.streams.num.stream.threads" : "4",
+    "ksql.timestamp.throw.on.invalid" : "false",
+    "ksql.authorization.cache.max.entries" : "10000",
+    "ksql.metrics.tags.custom" : "",
+    "ksql.pull.queries.enable" : "true",
+    "ksql.udfs.enabled" : "true",
+    "ksql.udf.enable.security.manager" : "true",
+    "ksql.connect.worker.config" : "",
+    "ksql.sink.window.change.log.additional.retention" : "1000000",
+    "ksql.readonly.topics" : "_confluent.*,__confluent.*,_schemas,__consumer_offsets,__transaction_state,connect-configs,connect-offsets,connect-status,connect-statuses",
+    "ksql.udf.collect.metrics" : "false",
+    "ksql.persistent.prefix" : "query_",
+    "ksql.query.persistent.active.limit" : "2147483647",
+    "ksql.error.classifier.regex" : ""
+  }
+}
\ No newline at end of file
diff --git a/ksqldb-functional-tests/src/test/resources/historical_plans/replace_-_regexp_replace/6.0.0_1591049420147/spec.json b/ksqldb-functional-tests/src/test/resources/historical_plans/replace_-_regexp_replace/6.0.0_1591049420147/spec.json
new file mode 100644
index 000000000000..0516467812df
--- /dev/null
+++ b/ksqldb-functional-tests/src/test/resources/historical_plans/replace_-_regexp_replace/6.0.0_1591049420147/spec.json
@@ -0,0 +1,103 @@
+{
+  "version" : "6.0.0",
+  "timestamp" : 1591049420147,
+  "path" : "query-validation-tests/replace.json",
+  "schemas" : {
+    "CSAS_OUTPUT_0.KsqlTopic.Source" : "STRUCT<INPUT_STRING VARCHAR, PATTERN VARCHAR> NOT NULL",
+    "CSAS_OUTPUT_0.OUTPUT" : "STRUCT<EXTRACTED VARCHAR> NOT NULL"
+  },
+  "testCase" : {
+    "name" : "regexp_replace",
+    "inputs" : [ {
+      "topic" : "test_topic",
+      "key" : "",
+      "value" : {
+        "input_string" : "baababaa",
+        "pattern" : "(ab)+"
+      }
+    }, {
+      "topic" : "test_topic",
+      "key" : "",
+      "value" : {
+        "input_string" : "baabbabaa",
+        "pattern" : "(ab)+"
+      }
+    }, {
+      "topic" : "test_topic",
+      "key" : "",
+      "value" : {
+        "input_string" : null,
+        "pattern" : "(ab)+"
+      }
+    }, {
+      "topic" : "test_topic",
+      "key" : "",
+      "value" : {
+        "input_string" : "baababaa",
+        "pattern" : null
+      }
+    } ],
+    "outputs" : [ {
+      "topic" : "OUTPUT",
+      "key" : "",
+      "value" : {
+        "EXTRACTED" : "bacataa"
+      }
+    }, {
+      "topic" : "OUTPUT",
+      "key" : "",
+      "value" : {
+        "EXTRACTED" : "bacatbcataa"
+      }
+    }, {
+      "topic" : "OUTPUT",
+      "key" : "",
+      "value" : {
+        "EXTRACTED" : null
+      }
+    }, {
+      "topic" : "OUTPUT",
+      "key" : "",
+      "value" : {
+        "EXTRACTED" : null
+      }
+    } ],
+    "topics" : [ {
+      "name" : "OUTPUT",
+      "replicas" : 1,
+      "numPartitions" : 4
+    }, {
+      "name" : "test_topic",
+      "replicas" : 1,
+      "numPartitions" : 4
+    } ],
+    "statements" : [ "CREATE STREAM TEST (K STRING KEY, input_string VARCHAR, pattern VARCHAR) WITH (kafka_topic='test_topic', value_format='JSON');", "CREATE STREAM OUTPUT AS SELECT K, REGEXP_REPLACE(input_string, pattern, 'cat') AS EXTRACTED FROM TEST;" ],
+    "post" : {
+      "topics" : {
+        "topics" : [ {
+          "name" : "OUTPUT",
+          "keyFormat" : {
+            "formatInfo" : {
+              "format" : "KAFKA"
+            }
+          },
+          "valueFormat" : {
+            "format" : "JSON"
+          },
+          "partitions" : 4
+        }, {
+          "name" : "test_topic",
+          "keyFormat" : {
+            "formatInfo" : {
+              "format" : "KAFKA"
+            }
+          },
+          "valueFormat" : {
+            "format" : "JSON"
+          },
+          "partitions" : 4
+        } ]
+      }
+    }
+  }
+}
\ No newline at end of file
diff --git a/ksqldb-functional-tests/src/test/resources/historical_plans/replace_-_regexp_replace/6.0.0_1591049420147/topology b/ksqldb-functional-tests/src/test/resources/historical_plans/replace_-_regexp_replace/6.0.0_1591049420147/topology
new file mode 100644
index 000000000000..441a8f282644
--- /dev/null
+++ b/ksqldb-functional-tests/src/test/resources/historical_plans/replace_-_regexp_replace/6.0.0_1591049420147/topology
@@ -0,0 +1,13 @@
+Topologies:
+   Sub-topology: 0
+    Source: KSTREAM-SOURCE-0000000000 (topics: [test_topic])
+      --> KSTREAM-TRANSFORMVALUES-0000000001
+    Processor: KSTREAM-TRANSFORMVALUES-0000000001 (stores: [])
+      --> Project
+      <-- KSTREAM-SOURCE-0000000000
+    Processor: Project (stores: [])
+      --> KSTREAM-SINK-0000000003
+      <-- KSTREAM-TRANSFORMVALUES-0000000001
+    Sink: KSTREAM-SINK-0000000003 (topic: OUTPUT)
+      <-- Project
+
diff --git a/ksqldb-functional-tests/src/test/resources/query-validation-tests/replace.json b/ksqldb-functional-tests/src/test/resources/query-validation-tests/replace.json
index 216f9ae873ba..f71f620fa15d 100644
--- a/ksqldb-functional-tests/src/test/resources/query-validation-tests/replace.json
+++ b/ksqldb-functional-tests/src/test/resources/query-validation-tests/replace.json
@@ -23,6 +23,25 @@
         {"topic": "OUTPUT", "value": {"REPLACE":null, "REPLACE_NULL":null, "REPLACE_W_NULL":null}},
         {"topic": "OUTPUT", "value": {"REPLACE":"popcorn", "REPLACE_NULL":null, "REPLACE_W_NULL":null}}
       ]
+    },
+    {
+      "name": "regexp_replace",
+      "statements": [
+        "CREATE STREAM TEST (K STRING KEY, input_string VARCHAR, pattern VARCHAR) WITH (kafka_topic='test_topic', value_format='JSON');",
+        "CREATE STREAM OUTPUT AS SELECT K, REGEXP_REPLACE(input_string, pattern, 'cat') AS EXTRACTED FROM TEST;"
+      ],
+      "inputs": [
+        {"topic": "test_topic", "value": {"input_string": "baababaa", "pattern": "(ab)+"}},
+        {"topic": "test_topic", "value": {"input_string": "baabbabaa", "pattern": "(ab)+"}},
+        {"topic": "test_topic", "value": {"input_string": null, "pattern": "(ab)+"}},
+        {"topic": "test_topic", "value": {"input_string": "baababaa", "pattern": null}}
+      ],
+      "outputs": [
+        {"topic": "OUTPUT", "value": {"EXTRACTED": "bacataa"}},
+        {"topic": "OUTPUT", "value": {"EXTRACTED": "bacatbcataa"}},
+        {"topic": "OUTPUT", "value": {"EXTRACTED": null}},
+        {"topic": "OUTPUT", "value": {"EXTRACTED": null}}
+      ]
     }
   ]
 }
\ No newline at end of file