diff --git a/docs/reference/query-dsl/queries/mlt-field-query.asciidoc b/docs/reference/query-dsl/queries/mlt-field-query.asciidoc
index e4f28bbda5b..fdcb735197f 100644
--- a/docs/reference/query-dsl/queries/mlt-field-query.asciidoc
+++ b/docs/reference/query-dsl/queries/mlt-field-query.asciidoc
@@ -58,7 +58,8 @@ ignored. Defaults to `0`. (Old name "min_word_len" is deprecated)
 ignored. Defaults to unbounded (`0`). (Old name "max_word_len" is deprecated)
 
 |`boost_terms` |Sets the boost factor to use when boosting terms.
-Defaults to `1`.
+Defaults to deactivated (`0`). Any other value activates boosting with given
+boost factor.
 
 |`boost` |Sets the boost value of the query. Defaults to `1.0`.
 
diff --git a/docs/reference/query-dsl/queries/mlt-query.asciidoc b/docs/reference/query-dsl/queries/mlt-query.asciidoc
index bea704a620d..b72a6fc4cab 100644
--- a/docs/reference/query-dsl/queries/mlt-query.asciidoc
+++ b/docs/reference/query-dsl/queries/mlt-query.asciidoc
@@ -57,7 +57,8 @@ ignored. Defaults to `0`.(Old name "min_word_len" is deprecated)
 ignored. Defaults to unbounded (`0`). (Old name "max_word_len" is deprecated)
 
 |`boost_terms` |Sets the boost factor to use when boosting terms.
-Defaults to `1`.
+Defaults to deactivated (`0`). Any other value activates boosting with given
+boost factor.
 
 |`boost` |Sets the boost value of the query. Defaults to `1.0`.
 
diff --git a/src/main/java/org/elasticsearch/index/query/MoreLikeThisFieldQueryParser.java b/src/main/java/org/elasticsearch/index/query/MoreLikeThisFieldQueryParser.java
index 7e465a590b4..ca714490325 100644
--- a/src/main/java/org/elasticsearch/index/query/MoreLikeThisFieldQueryParser.java
+++ b/src/main/java/org/elasticsearch/index/query/MoreLikeThisFieldQueryParser.java
@@ -91,8 +91,11 @@ public class MoreLikeThisFieldQueryParser implements QueryParser {
                 } else if (MoreLikeThisQueryParser.Fields.MAX_WORD_LENGTH.match(currentFieldName,parseContext.parseFlags())) {
                     mltQuery.setMaxWordLen(parser.intValue());
                 } else if (MoreLikeThisQueryParser.Fields.BOOST_TERMS.match(currentFieldName,parseContext.parseFlags())) {
-                    mltQuery.setBoostTerms(true);
-                    mltQuery.setBoostTermsFactor(parser.floatValue());
+                    float boostFactor = parser.floatValue();
+                    if (boostFactor != 0) {
+                        mltQuery.setBoostTerms(true);
+                        mltQuery.setBoostTermsFactor(boostFactor);
+                    }
                 } else if (MoreLikeThisQueryParser.Fields.PERCENT_TERMS_TO_MATCH.match(currentFieldName,parseContext.parseFlags())) {
                     mltQuery.setPercentTermsToMatch(parser.floatValue());
                 } else if ("analyzer".equals(currentFieldName)) {
diff --git a/src/main/java/org/elasticsearch/index/query/MoreLikeThisQueryParser.java b/src/main/java/org/elasticsearch/index/query/MoreLikeThisQueryParser.java
index 207652926cc..5385a91c507 100644
--- a/src/main/java/org/elasticsearch/index/query/MoreLikeThisQueryParser.java
+++ b/src/main/java/org/elasticsearch/index/query/MoreLikeThisQueryParser.java
@@ -99,8 +99,11 @@ public class MoreLikeThisQueryParser implements QueryParser {
                 } else if (Fields.MAX_WORD_LENGTH.match(currentFieldName, parseContext.parseFlags())) {
                     mltQuery.setMaxWordLen(parser.intValue());
                 } else if (Fields.BOOST_TERMS.match(currentFieldName, parseContext.parseFlags())) {
-                    mltQuery.setBoostTerms(true);
-                    mltQuery.setBoostTermsFactor(parser.floatValue());
+                    float boostFactor = parser.floatValue();
+                    if (boostFactor != 0) {
+                        mltQuery.setBoostTerms(true);
+                        mltQuery.setBoostTermsFactor(boostFactor);
+                    }
                 } else if (Fields.PERCENT_TERMS_TO_MATCH.match(currentFieldName, parseContext.parseFlags())) {
                     mltQuery.setPercentTermsToMatch(parser.floatValue());
                 } else if ("analyzer".equals(currentFieldName)) {