diff --git a/Dockerfile b/Dockerfile
index 16915d7..c2fddc0 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -21,6 +21,7 @@ ENV S3_S3V4 'no'
 ENV SCHEDULE ''
 ENV PASSPHRASE ''
 ENV BACKUP_KEEP_DAYS ''
+ENV BACKUP_ALL 'false'
 
 ADD src/run.sh run.sh
 ADD src/env.sh env.sh
diff --git a/README.md b/README.md
index 0164acf..a516de6 100644
--- a/README.md
+++ b/README.md
@@ -17,13 +17,14 @@ services:
       SCHEDULE: '@weekly'     # optional
       BACKUP_KEEP_DAYS: 7     # optional
       PASSPHRASE: passphrase  # optional
+      BACKUP_ALL: 'false'     # optional
       S3_REGION: region
       S3_ACCESS_KEY_ID: key
       S3_SECRET_ACCESS_KEY: secret
       S3_BUCKET: my-bucket
       S3_PREFIX: backup
       POSTGRES_HOST: postgres
-      POSTGRES_DATABASE: dbname
+      POSTGRES_DATABASE: dbname # optional if BACKUP_ALL is 'true'
       POSTGRES_USER: user
       POSTGRES_PASSWORD: password
 ```
@@ -31,6 +32,7 @@ services:
 - Images are tagged by the major PostgreSQL version supported: `11`, `12`, `13`, `14`, or `15`.
 - The `SCHEDULE` variable determines backup frequency. See go-cron schedules documentation [here](http://godoc.org/github.com/robfig/cron#hdr-Predefined_schedules). Omit to run the backup immediately and then exit.
 - If `PASSPHRASE` is provided, the backup will be encrypted using GPG.
+- If `BACKUP_ALL` is `'true'`, all databases will be backed up. Otherwise, only `POSTGRES_DATABASE` will be backed up.
 - Run `docker exec <container name> sh backup.sh` to trigger a backup ad-hoc.
 - If `BACKUP_KEEP_DAYS` is set, backups older than this many days will be deleted from S3.
 - Set `S3_ENDPOINT` if you're using a non-AWS S3-compatible storage provider.
diff --git a/docker-compose.yaml b/docker-compose.yaml
index 16ac481..4ea3864 100644
--- a/docker-compose.yaml
+++ b/docker-compose.yaml
@@ -17,12 +17,13 @@ services:
       SCHEDULE: '@weekly'     # optional
       BACKUP_KEEP_DAYS: 7     # optional
       PASSPHRASE: passphrase  # optional
+      BACKUP_ALL: 'true'      # optional
       S3_REGION:
       S3_ACCESS_KEY_ID:
       S3_SECRET_ACCESS_KEY:
       S3_BUCKET:
       S3_PREFIX: backup
       POSTGRES_HOST: postgres
-      POSTGRES_DATABASE: postgres
+      POSTGRES_DATABASE: postgres # optional if BACKUP_ALL is true
       POSTGRES_USER: user
       POSTGRES_PASSWORD: password
diff --git a/src/backup.sh b/src/backup.sh
index ff1bf15..b7cbff8 100644
--- a/src/backup.sh
+++ b/src/backup.sh
@@ -5,27 +5,40 @@ set -o pipefail
 
 source ./env.sh
 
-echo "Creating backup of $POSTGRES_DATABASE database..."
-pg_dump --format=custom \
-        -h $POSTGRES_HOST \
-        -p $POSTGRES_PORT \
-        -U $POSTGRES_USER \
-        -d $POSTGRES_DATABASE \
-        $PGDUMP_EXTRA_OPTS \
-        > db.dump
+if [ "$BACKUP_ALL" = "true" ]; then
+  echo "Creating backup of all databases..."
+  file_ext="dump.gz"
+  pg_dumpall --clean \
+             -h $POSTGRES_HOST \
+             -p $POSTGRES_PORT \
+             -U $POSTGRES_USER \
+             $PGDUMP_EXTRA_OPTS \
+             > db.dump
+  gzip db.dump
+else
+  echo "Creating backup of $POSTGRES_DATABASE database..."
+  file_ext="dump"
+  pg_dump --format=custom \
+          -h $POSTGRES_HOST \
+          -p $POSTGRES_PORT \
+          -U $POSTGRES_USER \
+          -d $POSTGRES_DATABASE \
+          $PGDUMP_EXTRA_OPTS \
+          > db.dump
+fi
 
 timestamp=$(date +"%Y-%m-%dT%H:%M:%S")
-s3_uri_base="s3://${S3_BUCKET}/${S3_PREFIX}/${POSTGRES_DATABASE}_${timestamp}.dump"
+s3_uri_base="s3://${S3_BUCKET}/${S3_PREFIX}/${POSTGRES_DATABASE}_${timestamp}.${file_ext}"
 
 if [ -n "$PASSPHRASE" ]; then
   echo "Encrypting backup..."
-  rm -f db.dump.gpg
-  gpg --symmetric --batch --passphrase "$PASSPHRASE" db.dump
-  rm db.dump
-  local_file="db.dump.gpg"
+  rm -f db.$file_ext.gpg
+  gpg --symmetric --batch --passphrase "$PASSPHRASE" db.$file_ext
+  rm db.$file_ext
+  local_file="db.${file_ext}.gpg"
   s3_uri="${s3_uri_base}.gpg"
 else
-  local_file="db.dump"
+  local_file="db.${file_ext}"
   s3_uri="$s3_uri_base"
 fi
 
diff --git a/src/env.sh b/src/env.sh
index af495e4..7a1ab9e 100644
--- a/src/env.sh
+++ b/src/env.sh
@@ -3,7 +3,7 @@ if [ -z "$S3_BUCKET" ]; then
   exit 1
 fi
 
-if [ -z "$POSTGRES_DATABASE" ]; then
+if [ "$BACKUP_ALL" != "true" ] && [ -z "$POSTGRES_DATABASE" ]; then
   echo "You need to set the POSTGRES_DATABASE environment variable."
   exit 1
 fi
diff --git a/src/restore.sh b/src/restore.sh
index 3040146..9c1b899 100644
--- a/src/restore.sh
+++ b/src/restore.sh
@@ -7,10 +7,16 @@ source ./env.sh
 
 s3_uri_base="s3://${S3_BUCKET}/${S3_PREFIX}"
 
+if [ "$BACKUP_ALL" = "true" ]; then
+  file_ext=".dump.gz"
+else
+  file_ext=".dump"
+fi
+
 if [ -z "$PASSPHRASE" ]; then
-  file_type=".dump"
+  file_type=$file_ext
 else
-  file_type=".dump.gpg"
+  file_type="${file_ext}.gpg"
 fi
 
 if [ $# -eq 1 ]; then
@@ -31,14 +37,21 @@ aws $aws_args s3 cp "${s3_uri_base}/${key_suffix}" "db${file_type}"
 
 if [ -n "$PASSPHRASE" ]; then
   echo "Decrypting backup..."
-  gpg --decrypt --batch --passphrase "$PASSPHRASE" db.dump.gpg > db.dump
-  rm db.dump.gpg
+  gpg --decrypt --batch --passphrase "$PASSPHRASE" db$file_type > db$file_ext
+  rm db$file_type
 fi
 
-conn_opts="-h $POSTGRES_HOST -p $POSTGRES_PORT -U $POSTGRES_USER -d $POSTGRES_DATABASE"
+conn_opts="-h $POSTGRES_HOST -p $POSTGRES_PORT -U $POSTGRES_USER"
+
+if [ "$BACKUP_ALL" = "true" ]; then
+  gunzip db.dump.gz
+  echo "Restoring all databases..."
+  psql -f db.dump $conn_opts
+else
+  echo "Restoring from backup..."
+  pg_restore $conn_opts -d $POSTGRES_DATABASE --clean --if-exists db.dump
+fi
 
-echo "Restoring from backup..."
-pg_restore $conn_opts --clean --if-exists db.dump
 rm db.dump
 
 echo "Restore complete."