diff --git a/group_vars/matrix_servers b/group_vars/matrix_servers
index 77876e33..4415c86c 100755
--- a/group_vars/matrix_servers
+++ b/group_vars/matrix_servers
@@ -1021,6 +1021,8 @@ matrix_ssl_pre_obtaining_required_service_name: "{{ 'matrix-dynamic-dns' if matr
 
 matrix_postgres_enabled: true
 
+matrix_postgres_architecture: "{{ matrix_architecture }}"
+
 # We unset this if internal Postgres disabled, which will cascade to some other variables
 # and tell users they need to set it (either here or in those variables).
 matrix_postgres_connection_hostname: "{{ 'matrix-postgres' if matrix_postgres_enabled else '' }}"
diff --git a/roles/matrix-postgres/defaults/main.yml b/roles/matrix-postgres/defaults/main.yml
index 07eeffad..21891583 100644
--- a/roles/matrix-postgres/defaults/main.yml
+++ b/roles/matrix-postgres/defaults/main.yml
@@ -9,11 +9,19 @@ matrix_postgres_db_name: "matrix"
 matrix_postgres_base_path: "{{ matrix_base_data_path }}/postgres"
 matrix_postgres_data_path: "{{ matrix_postgres_base_path }}/data"
 
-matrix_postgres_docker_image_v9: "docker.io/postgres:9.6.20-alpine"
-matrix_postgres_docker_image_v10: "docker.io/postgres:10.15-alpine"
-matrix_postgres_docker_image_v11: "docker.io/postgres:11.10-alpine"
-matrix_postgres_docker_image_v12: "docker.io/postgres:12.5-alpine"
-matrix_postgres_docker_image_v13: "docker.io/postgres:13.1-alpine"
+matrix_postgres_architecture: amd64
+
+# matrix_postgres_docker_image_suffix controls whether we use Alpine-based images (`-alpine`) or the normal Debian-based images.
+# Alpine-based Postgres images are smaller and we usually prefer them, but they don't work on ARM32 (tested on a Raspberry Pi 3 running Raspbian 10.7).
+# On ARM32, `-alpine` images fail with the following error:
+# > LOG:  startup process (PID 37) was terminated by signal 11: Segmentation fault
+matrix_postgres_docker_image_suffix: "{{ '-alpine' if matrix_postgres_architecture in ['amd64', 'arm64'] else '' }}"
+
+matrix_postgres_docker_image_v9: "docker.io/postgres:9.6.20{{ matrix_postgres_docker_image_suffix }}"
+matrix_postgres_docker_image_v10: "docker.io/postgres:10.15{{ matrix_postgres_docker_image_suffix }}"
+matrix_postgres_docker_image_v11: "docker.io/postgres:11.10{{ matrix_postgres_docker_image_suffix }}"
+matrix_postgres_docker_image_v12: "docker.io/postgres:12.5{{ matrix_postgres_docker_image_suffix }}"
+matrix_postgres_docker_image_v13: "docker.io/postgres:13.1{{ matrix_postgres_docker_image_suffix }}"
 matrix_postgres_docker_image_latest: "{{ matrix_postgres_docker_image_v13 }}"
 
 # This variable is assigned at runtime. Overriding its value has no effect.