diff --git a/2.7/windows/windowsservercore-1709/Dockerfile b/2.7/windows/windowsservercore-1709/Dockerfile
index 815ceb021..df1fc8678 100644
--- a/2.7/windows/windowsservercore-1709/Dockerfile
+++ b/2.7/windows/windowsservercore-1709/Dockerfile
@@ -7,6 +7,7 @@ ENV PYTHON_RELEASE 2.7.14
 
 RUN $url = ('https://www.python.org/ftp/python/{0}/python-{1}.amd64.msi' -f $env:PYTHON_RELEASE, $env:PYTHON_VERSION); \
 	Write-Host ('Downloading {0} ...' -f $url); \
+	[Net.ServicePointManager]::SecurityProtocol = [Net.SecurityProtocolType]::Tls12; \
 	Invoke-WebRequest -Uri $url -OutFile 'python.msi'; \
 	\
 	Write-Host 'Installing ...'; \
diff --git a/2.7/windows/windowsservercore-ltsc2016/Dockerfile b/2.7/windows/windowsservercore-ltsc2016/Dockerfile
index adf0ab74b..adc673b2f 100644
--- a/2.7/windows/windowsservercore-ltsc2016/Dockerfile
+++ b/2.7/windows/windowsservercore-ltsc2016/Dockerfile
@@ -7,6 +7,7 @@ ENV PYTHON_RELEASE 2.7.14
 
 RUN $url = ('https://www.python.org/ftp/python/{0}/python-{1}.amd64.msi' -f $env:PYTHON_RELEASE, $env:PYTHON_VERSION); \
 	Write-Host ('Downloading {0} ...' -f $url); \
+	[Net.ServicePointManager]::SecurityProtocol = [Net.SecurityProtocolType]::Tls12; \
 	Invoke-WebRequest -Uri $url -OutFile 'python.msi'; \
 	\
 	Write-Host 'Installing ...'; \
diff --git a/3.6/windows/windowsservercore-1709/Dockerfile b/3.6/windows/windowsservercore-1709/Dockerfile
index 8a458d7ea..1507edf30 100644
--- a/3.6/windows/windowsservercore-1709/Dockerfile
+++ b/3.6/windows/windowsservercore-1709/Dockerfile
@@ -13,6 +13,7 @@ ENV PYTHON_RELEASE 3.6.5
 
 RUN $url = ('https://www.python.org/ftp/python/{0}/python-{1}-amd64.exe' -f $env:PYTHON_RELEASE, $env:PYTHON_VERSION); \
 	Write-Host ('Downloading {0} ...' -f $url); \
+	[Net.ServicePointManager]::SecurityProtocol = [Net.SecurityProtocolType]::Tls12; \
 	Invoke-WebRequest -Uri $url -OutFile 'python.exe'; \
 	\
 	Write-Host 'Installing ...'; \
diff --git a/3.6/windows/windowsservercore-ltsc2016/Dockerfile b/3.6/windows/windowsservercore-ltsc2016/Dockerfile
index 52528816f..c1c0833e2 100644
--- a/3.6/windows/windowsservercore-ltsc2016/Dockerfile
+++ b/3.6/windows/windowsservercore-ltsc2016/Dockerfile
@@ -13,6 +13,7 @@ ENV PYTHON_RELEASE 3.6.5
 
 RUN $url = ('https://www.python.org/ftp/python/{0}/python-{1}-amd64.exe' -f $env:PYTHON_RELEASE, $env:PYTHON_VERSION); \
 	Write-Host ('Downloading {0} ...' -f $url); \
+	[Net.ServicePointManager]::SecurityProtocol = [Net.SecurityProtocolType]::Tls12; \
 	Invoke-WebRequest -Uri $url -OutFile 'python.exe'; \
 	\
 	Write-Host 'Installing ...'; \
diff --git a/3.7-rc/windows/windowsservercore-1709/Dockerfile b/3.7-rc/windows/windowsservercore-1709/Dockerfile
index 2be2f06ee..3d20988f6 100644
--- a/3.7-rc/windows/windowsservercore-1709/Dockerfile
+++ b/3.7-rc/windows/windowsservercore-1709/Dockerfile
@@ -13,6 +13,7 @@ ENV PYTHON_RELEASE 3.7.0
 
 RUN $url = ('https://www.python.org/ftp/python/{0}/python-{1}-amd64.exe' -f $env:PYTHON_RELEASE, $env:PYTHON_VERSION); \
 	Write-Host ('Downloading {0} ...' -f $url); \
+	[Net.ServicePointManager]::SecurityProtocol = [Net.SecurityProtocolType]::Tls12; \
 	Invoke-WebRequest -Uri $url -OutFile 'python.exe'; \
 	\
 	Write-Host 'Installing ...'; \
diff --git a/3.7-rc/windows/windowsservercore-ltsc2016/Dockerfile b/3.7-rc/windows/windowsservercore-ltsc2016/Dockerfile
index 02463bc4a..cea305fa8 100644
--- a/3.7-rc/windows/windowsservercore-ltsc2016/Dockerfile
+++ b/3.7-rc/windows/windowsservercore-ltsc2016/Dockerfile
@@ -13,6 +13,7 @@ ENV PYTHON_RELEASE 3.7.0
 
 RUN $url = ('https://www.python.org/ftp/python/{0}/python-{1}-amd64.exe' -f $env:PYTHON_RELEASE, $env:PYTHON_VERSION); \
 	Write-Host ('Downloading {0} ...' -f $url); \
+	[Net.ServicePointManager]::SecurityProtocol = [Net.SecurityProtocolType]::Tls12; \
 	Invoke-WebRequest -Uri $url -OutFile 'python.exe'; \
 	\
 	Write-Host 'Installing ...'; \
diff --git a/Dockerfile-windowsservercore.template b/Dockerfile-windowsservercore.template
index 239816906..6570ff653 100644
--- a/Dockerfile-windowsservercore.template
+++ b/Dockerfile-windowsservercore.template
@@ -7,6 +7,7 @@ ENV PYTHON_RELEASE %%PLACEHOLDER%%
 
 RUN $url = ('https://www.python.org/ftp/python/{0}/python-{1}-amd64.exe' -f $env:PYTHON_RELEASE, $env:PYTHON_VERSION); \
 	Write-Host ('Downloading {0} ...' -f $url); \
+	[Net.ServicePointManager]::SecurityProtocol = [Net.SecurityProtocolType]::Tls12; \
 	Invoke-WebRequest -Uri $url -OutFile 'python.exe'; \
 	\
 	Write-Host 'Installing ...'; \