diff --git a/CHANGELOG.md b/CHANGELOG.md
index d1332976..028bffe4 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -6,6 +6,10 @@ All notable changes to this project will be documented in this file. The format
 
 > **Note**: Changes and additions listed here are contained in the `:edge` image tag. These changes may not be as stable as released changes.
 
+### Added
+
+- New environment variable `MARK_SPAM_AS_READ`. When set to `1`, marks incoming junk as "read" to avoid unwanted notification of junk as new mail ([#3489](https://github.com/docker-mailserver/docker-mailserver/pull/3489))
+
 ## [v12.1.0](https://github.com/docker-mailserver/docker-mailserver/releases/tag/v12.1.0)
 
 ### Added
diff --git a/docs/content/config/environment.md b/docs/content/config/environment.md
index b81cef12..bea02ecb 100644
--- a/docs/content/config/environment.md
+++ b/docs/content/config/environment.md
@@ -309,6 +309,18 @@ will be automatically moved to the Junk folder (with the help of a Sieve script)
 - 0 => Spam messages will be delivered in the mailbox.
 - **1** => Spam messages will be delivered in the `Junk` folder.
 
+##### MARK_SPAM_AS_READ
+
+Enable to treat received spam as "read" (_avoids notification to MUA client of new mail_).
+
+Mail is received as spam when it has been marked with either header:
+
+1. `X-Spam: Yes` (_by Rspamd_)
+2. `X-Spam-Flag: YES` (_by SpamAssassin - requires [`SPAMASSASSIN_SPAM_TO_INBOX=1`](#spamassassin_spam_to_inbox)_)
+
+- **0** => disabled
+- 1 => Spam messages will be marked as read
+
 #### Rspamd
 
 ##### ENABLE_RSPAMD
diff --git a/docs/content/config/security/rspamd.md b/docs/content/config/security/rspamd.md
index d1d0987e..7876b998 100644
--- a/docs/content/config/security/rspamd.md
+++ b/docs/content/config/security/rspamd.md
@@ -27,6 +27,7 @@ The following environment variables are related to Rspamd:
 6. [`RSPAMD_HFILTER_HOSTNAME_UNKNOWN_SCORE`](../environment.md#rspamd_hfilter_hostname_unknown_score)
 7. [`RSPAMD_LEARN`](../environment.md#rspamd_learn)
 8. [`MOVE_SPAM_TO_JUNK`](../environment.md#move_spam_to_junk)
+9. [`MARK_SPAM_AS_READ`](../environment.md#mark_spam_as_read)
 
 With these variables, you can enable Rspamd itself and you can enable / disable certain features related to Rspamd.
 
diff --git a/mailserver.env b/mailserver.env
index cb040b9f..6f270af4 100644
--- a/mailserver.env
+++ b/mailserver.env
@@ -368,6 +368,9 @@ ENABLE_SPAMASSASSIN_KAM=0
 # spam messages will be moved in the Junk folder (SPAMASSASSIN_SPAM_TO_INBOX=1 required)
 MOVE_SPAM_TO_JUNK=1
 
+# spam messages wil be marked as read
+MARK_SPAM_AS_READ=0
+
 # add spam info headers if at, or above that level:
 SA_TAG=2.0
 
diff --git a/target/scripts/start-mailserver.sh b/target/scripts/start-mailserver.sh
index a002c6c3..e41ae71e 100755
--- a/target/scripts/start-mailserver.sh
+++ b/target/scripts/start-mailserver.sh
@@ -48,6 +48,7 @@ function _register_functions() {
     _register_setup_function '_setup_dovecot_dhparam'
     _register_setup_function '_setup_dovecot_quota'
     _register_setup_function '_setup_spam_to_junk'
+    _register_setup_function '_setup_spam_mark_as_read'
   fi
 
   case "${ACCOUNT_PROVISIONER}" in
diff --git a/target/scripts/startup/setup.d/security/misc.sh b/target/scripts/startup/setup.d/security/misc.sh
index b1fa4860..78c1e60a 100644
--- a/target/scripts/startup/setup.d/security/misc.sh
+++ b/target/scripts/startup/setup.d/security/misc.sh
@@ -271,3 +271,28 @@ EOF
     _log 'debug' 'Spam emails will not be moved to the Junk folder'
   fi
 }
+
+function _setup_spam_mark_as_read() {
+  if [[ ${MARK_SPAM_AS_READ} -eq 1 ]]; then
+    _log 'debug' 'Spam emails will be marked as read'
+    mkdir -p /usr/lib/dovecot/sieve-global/after/
+
+    # Header support: `X-Spam-Flag` (SpamAssassin), `X-Spam` (Rspamd)
+    cat >/usr/lib/dovecot/sieve-global/after/spam_mark_as_read.sieve << EOF
+require ["mailbox","imap4flags"];
+
+if anyof (header :contains "X-Spam-Flag" "YES",
+          header :contains "X-Spam" "Yes") {
+    setflag "\\\\Seen";
+}
+EOF
+    sievec /usr/lib/dovecot/sieve-global/after/spam_mark_as_read.sieve
+    chown dovecot:root /usr/lib/dovecot/sieve-global/after/spam_mark_as_read.{sieve,svbin}
+
+    if [[ ${ENABLE_SPAMASSASSIN} -eq 1 ]] && [[ ${SPAMASSASSIN_SPAM_TO_INBOX} -eq 0 ]]; then
+      _log 'warning' "'SPAMASSASSIN_SPAM_TO_INBOX=0' but it is required to be 1 for 'MARK_SPAM_AS_READ=1' to work"
+    fi
+  else
+    _log 'debug' 'Spam emails will not be marked as read'
+  fi
+}
diff --git a/target/scripts/startup/variables-stack.sh b/target/scripts/startup/variables-stack.sh
index d6c5453c..a0d61242 100644
--- a/target/scripts/startup/variables-stack.sh
+++ b/target/scripts/startup/variables-stack.sh
@@ -46,6 +46,7 @@ function __environment_variables_general_setup() {
   VARS[CLAMAV_MESSAGE_SIZE_LIMIT]="${CLAMAV_MESSAGE_SIZE_LIMIT:=25M}"
   VARS[FAIL2BAN_BLOCKTYPE]="${FAIL2BAN_BLOCKTYPE:=drop}"
   VARS[MOVE_SPAM_TO_JUNK]="${MOVE_SPAM_TO_JUNK:=1}"
+  VARS[MARK_SPAM_AS_READ]="${MARK_SPAM_AS_READ:=0}"
   VARS[POSTGREY_AUTO_WHITELIST_CLIENTS]="${POSTGREY_AUTO_WHITELIST_CLIENTS:=5}"
   VARS[POSTGREY_DELAY]="${POSTGREY_DELAY:=300}"
   VARS[POSTGREY_MAX_AGE]="${POSTGREY_MAX_AGE:=35}"
diff --git a/test/tests/parallel/set1/spam_virus/spam_junk_folder.bats b/test/tests/parallel/set1/spam_virus/spam_junk_folder.bats
index 237218e8..94a9b9c4 100644
--- a/test/tests/parallel/set1/spam_virus/spam_junk_folder.bats
+++ b/test/tests/parallel/set1/spam_virus/spam_junk_folder.bats
@@ -8,6 +8,7 @@ BATS_TEST_NAME_PREFIX='[Spam - Amavis] ENV SPAMASSASSIN_SPAM_TO_INBOX '
 CONTAINER1_NAME='dms-test_spam-amavis_bounced'
 CONTAINER2_NAME='dms-test_spam-amavis_env-move-spam-to-junk-0'
 CONTAINER3_NAME='dms-test_spam-amavis_env-move-spam-to-junk-1'
+CONTAINER4_NAME='dms-test_spam-amavis_env-mark-spam-as-read-1'
 
 function teardown() { _default_teardown ; }
 
@@ -69,6 +70,28 @@ function teardown() { _default_teardown ; }
   _should_receive_spam_at '/var/mail/localhost.localdomain/user1/.Junk/new/'
 }
 
+# NOTE: Same as test for `CONTAINER3_NAME`, only differing by ENV `MARK_SPAM_AS_READ=1` + `_should_receive_spam_at` location
+@test "(enabled + MARK_SPAM_AS_READ=1) should mark spam message as read" {
+  export CONTAINER_NAME=${CONTAINER4_NAME}
+
+  local CUSTOM_SETUP_ARGUMENTS=(
+    --env ENABLE_AMAVIS=1
+    --env ENABLE_SPAMASSASSIN=1
+    --env SA_SPAM_SUBJECT="SPAM: "
+    --env SPAMASSASSIN_SPAM_TO_INBOX=1
+    --env MARK_SPAM_AS_READ=1
+    --env PERMIT_DOCKER=container
+  )
+  _init_with_defaults
+  _common_container_setup 'CUSTOM_SETUP_ARGUMENTS'
+
+  _should_send_spam_message
+  _should_be_received_by_amavis 'Passed SPAM {RelayedTaggedInbound,Quarantined}'
+
+  # Should move delivered spam to Junk folder as read (`cur` instead of `new`)
+  _should_receive_spam_at '/var/mail/localhost.localdomain/user1/.Junk/cur/'
+}
+
 function _should_send_spam_message() {
   _wait_for_smtp_port_in_container
   _wait_for_tcp_port_in_container 10024 # port 10024 is for Amavis