diff --git a/3.2/Dockerfile b/3.2/Dockerfile
index 25f7d9b8..7c9fb140 100644
--- a/3.2/Dockerfile
+++ b/3.2/Dockerfile
@@ -72,7 +72,7 @@ RUN buildDeps=' \
 	&& apt-get update && apt-get install -y $buildDeps --no-install-recommends \
 	&& rm -rf /var/lib/apt/lists/* \
 	&& bundle install --without development test \
-	&& for adapter in mysql2 postgresql sqlite3; do \
+	&& for adapter in mysql2 postgresql sqlserver sqlite3; do \
 		echo "$RAILS_ENV:" > ./config/database.yml; \
 		echo "  adapter: $adapter" >> ./config/database.yml; \
 		bundle install --without development test; \
diff --git a/3.2/docker-entrypoint.sh b/3.2/docker-entrypoint.sh
index 5351c9dd..e0a4ff5a 100755
--- a/3.2/docker-entrypoint.sh
+++ b/3.2/docker-entrypoint.sh
@@ -28,6 +28,7 @@ case "$1" in
 		if [ ! -f './config/database.yml' ]; then
 			file_env 'REDMINE_DB_MYSQL'
 			file_env 'REDMINE_DB_POSTGRES'
+			file_env 'REDMINE_DB_SQLSERVER'
 			
 			if [ "$MYSQL_PORT_3306_TCP" ] && [ -z "$REDMINE_DB_MYSQL" ]; then
 				export REDMINE_DB_MYSQL='mysql'
@@ -51,9 +52,17 @@ case "$1" in
 				file_env 'REDMINE_DB_PASSWORD' "${POSTGRES_ENV_POSTGRES_PASSWORD}"
 				file_env 'REDMINE_DB_DATABASE' "${POSTGRES_ENV_POSTGRES_DB:-${REDMINE_DB_USERNAME:-}}"
 				file_env 'REDMINE_DB_ENCODING' 'utf8'
+			elif [ "$REDMINE_DB_SQLSERVER" ]; then
+				adapter='sqlserver'
+				host="$REDMINE_DB_SQLSERVER"
+				file_env 'REDMINE_DB_PORT' '1433'
+				file_env 'REDMINE_DB_USERNAME' ''
+				file_env 'REDMINE_DB_PASSWORD' ''
+				file_env 'REDMINE_DB_DATABASE' ''
+				file_env 'REDMINE_DB_ENCODING' ''
 			else
 				echo >&2
-				echo >&2 'warning: missing REDMINE_DB_MYSQL or REDMINE_DB_POSTGRES environment variables'
+				echo >&2 'warning: missing REDMINE_DB_MYSQL, REDMINE_DB_POSTGRES, or REDMINE_DB_SQLSERVER environment variables'
 				echo >&2
 				echo >&2 '*** Using sqlite3 as fallback. ***'
 				echo >&2
diff --git a/3.3/Dockerfile b/3.3/Dockerfile
index c2d48c50..9f591752 100644
--- a/3.3/Dockerfile
+++ b/3.3/Dockerfile
@@ -72,7 +72,7 @@ RUN buildDeps=' \
 	&& apt-get update && apt-get install -y $buildDeps --no-install-recommends \
 	&& rm -rf /var/lib/apt/lists/* \
 	&& bundle install --without development test \
-	&& for adapter in mysql2 postgresql sqlite3; do \
+	&& for adapter in mysql2 postgresql sqlserver sqlite3; do \
 		echo "$RAILS_ENV:" > ./config/database.yml; \
 		echo "  adapter: $adapter" >> ./config/database.yml; \
 		bundle install --without development test; \
diff --git a/3.3/docker-entrypoint.sh b/3.3/docker-entrypoint.sh
index 5351c9dd..e0a4ff5a 100755
--- a/3.3/docker-entrypoint.sh
+++ b/3.3/docker-entrypoint.sh
@@ -28,6 +28,7 @@ case "$1" in
 		if [ ! -f './config/database.yml' ]; then
 			file_env 'REDMINE_DB_MYSQL'
 			file_env 'REDMINE_DB_POSTGRES'
+			file_env 'REDMINE_DB_SQLSERVER'
 			
 			if [ "$MYSQL_PORT_3306_TCP" ] && [ -z "$REDMINE_DB_MYSQL" ]; then
 				export REDMINE_DB_MYSQL='mysql'
@@ -51,9 +52,17 @@ case "$1" in
 				file_env 'REDMINE_DB_PASSWORD' "${POSTGRES_ENV_POSTGRES_PASSWORD}"
 				file_env 'REDMINE_DB_DATABASE' "${POSTGRES_ENV_POSTGRES_DB:-${REDMINE_DB_USERNAME:-}}"
 				file_env 'REDMINE_DB_ENCODING' 'utf8'
+			elif [ "$REDMINE_DB_SQLSERVER" ]; then
+				adapter='sqlserver'
+				host="$REDMINE_DB_SQLSERVER"
+				file_env 'REDMINE_DB_PORT' '1433'
+				file_env 'REDMINE_DB_USERNAME' ''
+				file_env 'REDMINE_DB_PASSWORD' ''
+				file_env 'REDMINE_DB_DATABASE' ''
+				file_env 'REDMINE_DB_ENCODING' ''
 			else
 				echo >&2
-				echo >&2 'warning: missing REDMINE_DB_MYSQL or REDMINE_DB_POSTGRES environment variables'
+				echo >&2 'warning: missing REDMINE_DB_MYSQL, REDMINE_DB_POSTGRES, or REDMINE_DB_SQLSERVER environment variables'
 				echo >&2
 				echo >&2 '*** Using sqlite3 as fallback. ***'
 				echo >&2
diff --git a/3.4/Dockerfile b/3.4/Dockerfile
index 759ef291..8b4a55d3 100644
--- a/3.4/Dockerfile
+++ b/3.4/Dockerfile
@@ -72,7 +72,7 @@ RUN buildDeps=' \
 	&& apt-get update && apt-get install -y $buildDeps --no-install-recommends \
 	&& rm -rf /var/lib/apt/lists/* \
 	&& bundle install --without development test \
-	&& for adapter in mysql2 postgresql sqlite3; do \
+	&& for adapter in mysql2 postgresql sqlserver sqlite3; do \
 		echo "$RAILS_ENV:" > ./config/database.yml; \
 		echo "  adapter: $adapter" >> ./config/database.yml; \
 		bundle install --without development test; \
diff --git a/3.4/docker-entrypoint.sh b/3.4/docker-entrypoint.sh
index 5351c9dd..e0a4ff5a 100755
--- a/3.4/docker-entrypoint.sh
+++ b/3.4/docker-entrypoint.sh
@@ -28,6 +28,7 @@ case "$1" in
 		if [ ! -f './config/database.yml' ]; then
 			file_env 'REDMINE_DB_MYSQL'
 			file_env 'REDMINE_DB_POSTGRES'
+			file_env 'REDMINE_DB_SQLSERVER'
 			
 			if [ "$MYSQL_PORT_3306_TCP" ] && [ -z "$REDMINE_DB_MYSQL" ]; then
 				export REDMINE_DB_MYSQL='mysql'
@@ -51,9 +52,17 @@ case "$1" in
 				file_env 'REDMINE_DB_PASSWORD' "${POSTGRES_ENV_POSTGRES_PASSWORD}"
 				file_env 'REDMINE_DB_DATABASE' "${POSTGRES_ENV_POSTGRES_DB:-${REDMINE_DB_USERNAME:-}}"
 				file_env 'REDMINE_DB_ENCODING' 'utf8'
+			elif [ "$REDMINE_DB_SQLSERVER" ]; then
+				adapter='sqlserver'
+				host="$REDMINE_DB_SQLSERVER"
+				file_env 'REDMINE_DB_PORT' '1433'
+				file_env 'REDMINE_DB_USERNAME' ''
+				file_env 'REDMINE_DB_PASSWORD' ''
+				file_env 'REDMINE_DB_DATABASE' ''
+				file_env 'REDMINE_DB_ENCODING' ''
 			else
 				echo >&2
-				echo >&2 'warning: missing REDMINE_DB_MYSQL or REDMINE_DB_POSTGRES environment variables'
+				echo >&2 'warning: missing REDMINE_DB_MYSQL, REDMINE_DB_POSTGRES, or REDMINE_DB_SQLSERVER environment variables'
 				echo >&2
 				echo >&2 '*** Using sqlite3 as fallback. ***'
 				echo >&2
diff --git a/Dockerfile.template b/Dockerfile.template
index bd576b2c..3a0a4e02 100644
--- a/Dockerfile.template
+++ b/Dockerfile.template
@@ -72,7 +72,7 @@ RUN buildDeps=' \
 	&& apt-get update && apt-get install -y $buildDeps --no-install-recommends \
 	&& rm -rf /var/lib/apt/lists/* \
 	&& bundle install --without development test \
-	&& for adapter in mysql2 postgresql sqlite3; do \
+	&& for adapter in mysql2 postgresql sqlserver sqlite3; do \
 		echo "$RAILS_ENV:" > ./config/database.yml; \
 		echo "  adapter: $adapter" >> ./config/database.yml; \
 		bundle install --without development test; \
diff --git a/docker-entrypoint.sh b/docker-entrypoint.sh
index 5351c9dd..e0a4ff5a 100755
--- a/docker-entrypoint.sh
+++ b/docker-entrypoint.sh
@@ -28,6 +28,7 @@ case "$1" in
 		if [ ! -f './config/database.yml' ]; then
 			file_env 'REDMINE_DB_MYSQL'
 			file_env 'REDMINE_DB_POSTGRES'
+			file_env 'REDMINE_DB_SQLSERVER'
 			
 			if [ "$MYSQL_PORT_3306_TCP" ] && [ -z "$REDMINE_DB_MYSQL" ]; then
 				export REDMINE_DB_MYSQL='mysql'
@@ -51,9 +52,17 @@ case "$1" in
 				file_env 'REDMINE_DB_PASSWORD' "${POSTGRES_ENV_POSTGRES_PASSWORD}"
 				file_env 'REDMINE_DB_DATABASE' "${POSTGRES_ENV_POSTGRES_DB:-${REDMINE_DB_USERNAME:-}}"
 				file_env 'REDMINE_DB_ENCODING' 'utf8'
+			elif [ "$REDMINE_DB_SQLSERVER" ]; then
+				adapter='sqlserver'
+				host="$REDMINE_DB_SQLSERVER"
+				file_env 'REDMINE_DB_PORT' '1433'
+				file_env 'REDMINE_DB_USERNAME' ''
+				file_env 'REDMINE_DB_PASSWORD' ''
+				file_env 'REDMINE_DB_DATABASE' ''
+				file_env 'REDMINE_DB_ENCODING' ''
 			else
 				echo >&2
-				echo >&2 'warning: missing REDMINE_DB_MYSQL or REDMINE_DB_POSTGRES environment variables'
+				echo >&2 'warning: missing REDMINE_DB_MYSQL, REDMINE_DB_POSTGRES, or REDMINE_DB_SQLSERVER environment variables'
 				echo >&2
 				echo >&2 '*** Using sqlite3 as fallback. ***'
 				echo >&2