diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 8f7c6bffc2..b5ff21dfab 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -150,20 +150,20 @@ stages:
 
 # Debian
 
-.respdiff-debian-bullseye-amd64: &respdiff_debian_bullseye_amd64_image
-  image: "$CI_REGISTRY_IMAGE:debian-bullseye-amd64"
+.respdiff-debian-bookworm-amd64: &respdiff_debian_bookworm_amd64_image
+  image: "$CI_REGISTRY_IMAGE:debian-bookworm-amd64"
   <<: *linux_respdiff_amd64
 
-.debian-bullseye-amd64: &debian_bullseye_amd64_image
-  image: "$CI_REGISTRY_IMAGE:debian-bullseye-amd64"
+.debian-bookworm-amd64: &debian_bookworm_amd64_image
+  image: "$CI_REGISTRY_IMAGE:debian-bookworm-amd64"
   <<: *linux_amd64
 
-.tsan-debian-bullseye-amd64: &tsan_debian_bullseye_amd64_image
-  image: "$CI_REGISTRY_IMAGE:tsan-debian-bullseye-amd64"
+.tsan-debian-bookworm-amd64: &tsan_debian_bookworm_amd64_image
+  image: "$CI_REGISTRY_IMAGE:tsan-debian-bookworm-amd64"
   <<: *linux_amd64
 
-.debian-bullseye-amd64cross32: &debian_bullseye_amd64cross32_image
-  image: "$CI_REGISTRY_IMAGE:debian-bullseye-amd64cross32"
+.debian-bookworm-amd64cross32: &debian_bookworm_amd64cross32_image
+  image: "$CI_REGISTRY_IMAGE:debian-bookworm-amd64cross32"
   <<: *linux_amd64
 
 .debian-sid-amd64: &debian_sid_amd64_image
@@ -204,7 +204,7 @@ stages:
 # This is a meta image that is used as a base for non-specific jobs
 
 .base: &base_image
-  <<: *debian_bullseye_amd64_image
+  <<: *debian_bookworm_amd64_image
 
 ### QCOW2 Image Templates
 
@@ -627,7 +627,7 @@ tarball-create:
     - job: autoreconf
       artifacts: true
 
-# Jobs for doc builds on Debian 11 "bullseye" (amd64)
+# Jobs for doc builds on Debian 12 "bookworm" (amd64)
 
 docs:
   <<: *default_triggering_rules
@@ -788,48 +788,48 @@ gcc:tarball:nosphinx:
     - job: tarball-create
       artifacts: true
 
-# Jobs for regular GCC builds on Debian 11 "bullseye" (amd64)
+# Jobs for regular GCC builds on Debian 12 "bookworm" (amd64)
 
-gcc:bullseye:amd64:
+gcc:bookworm:amd64:
   variables:
     BUILD_CONTRIB: 1
     CC: gcc
     CFLAGS: "${CFLAGS_COMMON} --coverage -O0"
     EXTRA_CONFIGURE: "--with-libidn2 ${WITH_READLINE_LIBEDIT}"
     RUN_MAKE_INSTALL: 1
-  <<: *debian_bullseye_amd64_image
+  <<: *debian_bookworm_amd64_image
   <<: *build_job
 
-system:gcc:bullseye:amd64:
-  <<: *debian_bullseye_amd64_image
+system:gcc:bookworm:amd64:
+  <<: *debian_bookworm_amd64_image
   <<: *system_test_gcov_job
   variables:
     CI_ENABLE_ALL_TESTS: 1
   needs:
-    - job: unit:gcc:bullseye:amd64
+    - job: unit:gcc:bookworm:amd64
       artifacts: true
 
-unit:gcc:bullseye:amd64:
-  <<: *debian_bullseye_amd64_image
+unit:gcc:bookworm:amd64:
+  <<: *debian_bookworm_amd64_image
   <<: *unit_test_gcov_job
   variables:
     CI_ENABLE_ALL_TESTS: 1
   needs:
-    - job: gcc:bullseye:amd64
+    - job: gcc:bookworm:amd64
       artifacts: true
 
-# Build job for cross-compiled GCC builds on 64-bit Debian 11 "bullseye"
+# Build job for cross-compiled GCC builds on 64-bit Debian 12 "bookworm"
 # (amd64) with 32-bit BIND 9.
 
-gcc:bullseye:amd64cross32:
+gcc:bookworm:amd64cross32:
   variables:
     CFLAGS: "${CFLAGS_COMMON}"
     CROSS_COMPILATION: 1
     EXTRA_CONFIGURE: "--build=x86_64-linux-gnu --host=i686-linux-gnu --with-libidn2 ${WITH_READLINE_LIBEDIT}"
-  <<: *debian_bullseye_amd64cross32_image
+  <<: *debian_bookworm_amd64cross32_image
   <<: *build_job
 
-# Jobs for scan-build builds on Debian 11 "bullseye" (amd64)
+# Jobs for scan-build builds on Debian 12 "bookworm" (amd64)
 
 .scan_build: &scan_build
   - ${SCAN_BUILD} --html-title="BIND 9 ($CI_COMMIT_SHORT_SHA)"
@@ -915,7 +915,7 @@ unit:gcc:sid:amd64:
     - job: gcc:sid:amd64
       artifacts: true
 
-# Job for out-of-tree GCC build on Debian 11 "bullseye" (amd64)
+# Job for out-of-tree GCC build on Debian 12 "bookworm" (amd64)
 # Also tests configration option: --with-lmdb.
 
 gcc:out-of-tree:
@@ -949,7 +949,7 @@ unit:gcc:out-of-tree:
   <<: *unit_test_job
   <<: *api_schedules_tags_triggers_web_triggering_rules
 
-# Jobs for tarball GCC builds on Debian 11 "bullseye" (amd64)
+# Jobs for tarball GCC builds on Debian 12 "bookworm" (amd64)
 
 gcc:tarball:
   variables:
@@ -1148,7 +1148,7 @@ unit:gcc:tsan:
       artifacts: true
 
 clang:tsan:
-  <<: *tsan_debian_bullseye_amd64_image
+  <<: *tsan_debian_bookworm_amd64_image
   <<: *build_job
   variables:
     CC: "${CLANG}"
@@ -1159,7 +1159,7 @@ clang:tsan:
 system:clang:tsan:
   variables:
     TSAN_OPTIONS: "${TSAN_OPTIONS_DEBIAN}"
-  <<: *tsan_debian_bullseye_amd64_image
+  <<: *tsan_debian_bookworm_amd64_image
   <<: *system_test_tsan_job
   needs:
     - job: clang:tsan
@@ -1168,17 +1168,17 @@ system:clang:tsan:
 unit:clang:tsan:
   variables:
     TSAN_OPTIONS: "${TSAN_OPTIONS_DEBIAN}"
-  <<: *tsan_debian_bullseye_amd64_image
+  <<: *tsan_debian_bookworm_amd64_image
   <<: *unit_test_tsan_job
   needs:
     - job: clang:tsan
       artifacts: true
 
-# Jobs for Clang builds on Debian 11 "bullseye" (amd64)
+# Jobs for Clang builds on Debian 12 "bookworm" (amd64)
 # The -Wno-compound-token-split-by-macro option prevents warning when compiling
 # Perl DLZ module with Clang against Perl older than version 5.35.2.
 
-clang:bullseye:amd64:
+clang:bookworm:amd64:
   variables:
     BUILD_CONTRIB: 1
     CC: ${CLANG}
@@ -1186,27 +1186,27 @@ clang:bullseye:amd64:
     # See https://gitlab.isc.org/isc-projects/bind9/-/issues/3444
     EXTRA_CONFIGURE: "--without-jemalloc --disable-leak-detection"
     RUN_MAKE_INSTALL: 1
-  <<: *debian_bullseye_amd64_image
+  <<: *debian_bookworm_amd64_image
   <<: *build_job
 
-system:clang:bullseye:amd64:
+system:clang:bookworm:amd64:
   # Set up environment variables that allow the "keyfromlabel" system test to be run
   variables:
     DEFAULT_OPENSSL_CONF: "/etc/ssl/openssl.cnf"
     OPENSSL_CONF: "/var/tmp/etc/openssl.cnf"
     SOFTHSM2_CONF: "/var/tmp/softhsm2/softhsm2.conf"
     SOFTHSM2_MODULE: "/usr/lib/softhsm/libsofthsm2.so"
-  <<: *debian_bullseye_amd64_image
+  <<: *debian_bookworm_amd64_image
   <<: *system_test_job
   needs:
-    - job: clang:bullseye:amd64
+    - job: clang:bookworm:amd64
       artifacts: true
 
-unit:clang:bullseye:amd64:
-  <<: *debian_bullseye_amd64_image
+unit:clang:bookworm:amd64:
+  <<: *debian_bookworm_amd64_image
   <<: *unit_test_job
   needs:
-    - job: clang:bullseye:amd64
+    - job: clang:bookworm:amd64
       artifacts: true
 
 # Jobs for Clang builds on FreeBSD 12 (amd64)
@@ -1382,7 +1382,7 @@ coverity:
 respdiff-short:
   <<: *respdiff_job
   <<: *default_triggering_rules
-  <<: *debian_bullseye_amd64_image
+  <<: *debian_bookworm_amd64_image
   variables:
     CC: gcc
     CFLAGS: "${CFLAGS_COMMON} -Og -DISC_TRACK_PTHREADS_OBJECTS"
@@ -1393,7 +1393,7 @@ respdiff-short:
 respdiff-short:asan:
   <<: *respdiff_job
   <<: *default_triggering_rules
-  <<: *debian_bullseye_amd64_image
+  <<: *debian_bookworm_amd64_image
   variables:
     CC: gcc
     CFLAGS: "${CFLAGS_COMMON} -Og -fsanitize=address,undefined"
@@ -1406,7 +1406,7 @@ respdiff-short:asan:
 respdiff-short:tsan:
   <<: *respdiff_job
   <<: *default_triggering_rules
-  <<: *tsan_debian_bullseye_amd64_image
+  <<: *tsan_debian_bookworm_amd64_image
   variables:
     CC: gcc
     CFLAGS: "${CFLAGS_COMMON} -Og -fsanitize=thread"
@@ -1423,7 +1423,7 @@ respdiff-short:tsan:
 respdiff-long:
   <<: *respdiff_job
   <<: *api_schedules_tags_triggers_web_triggering_rules
-  <<: *respdiff_debian_bullseye_amd64_image
+  <<: *respdiff_debian_bookworm_amd64_image
   variables:
     CC: gcc
     CFLAGS: "${CFLAGS_COMMON} -Og -DISC_TRACK_PTHREADS_OBJECTS"
@@ -1434,7 +1434,7 @@ respdiff-long:
 respdiff-long:asan:
   <<: *respdiff_job
   <<: *api_schedules_tags_triggers_web_triggering_rules
-  <<: *debian_bullseye_amd64_image
+  <<: *debian_bookworm_amd64_image
   variables:
     CC: gcc
     CFLAGS: "${CFLAGS_COMMON} -Og -fsanitize=address,undefined"
@@ -1447,7 +1447,7 @@ respdiff-long:asan:
 respdiff-long:tsan:
   <<: *respdiff_job
   <<: *api_schedules_tags_triggers_web_triggering_rules
-  <<: *tsan_debian_bullseye_amd64_image
+  <<: *tsan_debian_bookworm_amd64_image
   variables:
     CC: gcc
     CFLAGS: "${CFLAGS_COMMON} -Og -fsanitize=thread"
@@ -1464,7 +1464,7 @@ respdiff-long:tsan:
 respdiff-long-third-party:
   <<: *respdiff_job
   <<: *api_schedules_tags_triggers_web_triggering_rules
-  <<: *debian_bullseye_amd64_image
+  <<: *debian_bookworm_amd64_image
   variables:
     CC: gcc
     CFLAGS: "${CFLAGS_COMMON} -Og"
@@ -1653,7 +1653,7 @@ gcov:
   <<: *default_triggering_rules
   stage: postcheck
   needs:
-    - job: system:gcc:bullseye:amd64
+    - job: system:gcc:bookworm:amd64
       artifacts: true
   script:
     # *.gcno and *.gcda files generated for shared library objects are created
diff --git a/doc/arm/platforms.inc.rst b/doc/arm/platforms.inc.rst
index b9ff7d2e95..04e8405ca8 100644
--- a/doc/arm/platforms.inc.rst
+++ b/doc/arm/platforms.inc.rst
@@ -43,7 +43,7 @@ Regularly Tested Platforms
 Current versions of BIND 9 are fully supported and regularly tested on the
 following systems:
 
--  Debian 11
+-  Debian 12
 -  Ubuntu LTS 20.04, 22.04
 -  Fedora 38
 -  Red Hat Enterprise Linux / CentOS / Oracle Linux 8, 9
diff --git a/doc/arm/requirements.txt b/doc/arm/requirements.txt
index 3b12ea86fb..b1b322dff5 100644
--- a/doc/arm/requirements.txt
+++ b/doc/arm/requirements.txt
@@ -1,5 +1,5 @@
 # Make Read the Docs use the exact same package versions as in
-# registry.gitlab.isc.org/isc-projects/images/bind9:debian-bullseye-amd64
+# registry.gitlab.isc.org/isc-projects/images/bind9:debian-bookworm-amd64
 Sphinx==6.1.3
 docutils==0.18.1
 sphinx_rtd_theme==1.2.0
diff --git a/util/release-tarball-comparison.sh b/util/release-tarball-comparison.sh
index b4ef3aaec2..6d515b53a2 100755
--- a/util/release-tarball-comparison.sh
+++ b/util/release-tarball-comparison.sh
@@ -34,7 +34,7 @@ if [ -z "${GITLAB_USER}" ] || [ -z "${GITLAB_TOKEN}" ]; then
 fi
 
 # Create the container to work in.
-CONTAINER_ID=$(docker create --interactive debian:bullseye)
+CONTAINER_ID=$(docker create --interactive debian:bookworm)
 trap "docker container rm -f \${CONTAINER_ID} >/dev/null" EXIT
 docker start "${CONTAINER_ID}"