diff --git a/client/llb/exec.go b/client/llb/exec.go
index c1c82aa756da..decc0d7407f7 100644
--- a/client/llb/exec.go
+++ b/client/llb/exec.go
@@ -153,7 +153,13 @@ func (e *ExecOp) Marshal(ctx context.Context, c *Constraints) (digest.Digest, []
 	}
 	if c.Caps != nil {
 		if err := c.Caps.Supports(pb.CapExecMetaSetsDefaultPath); err != nil {
-			env = env.SetDefault("PATH", system.DefaultPathEnv)
+			os := "linux"
+			if c.Platform != nil {
+				os = c.Platform.OS
+			} else if e.constraints.Platform != nil {
+				os = e.constraints.Platform.OS
+			}
+			env = env.SetDefault("PATH", system.DefaultPathEnv(os))
 		} else {
 			addCap(&e.constraints, pb.CapExecMetaSetsDefaultPath)
 		}
diff --git a/examples/buildkit0/buildkit.go b/examples/buildkit0/buildkit.go
index 66fb750a5a97..dd094d15ec59 100644
--- a/examples/buildkit0/buildkit.go
+++ b/examples/buildkit0/buildkit.go
@@ -35,7 +35,7 @@ func main() {
 func goBuildBase() llb.State {
 	goAlpine := llb.Image("docker.io/library/golang:1.13-alpine")
 	return goAlpine.
-		AddEnv("PATH", "/usr/local/go/bin:"+system.DefaultPathEnv).
+		AddEnv("PATH", "/usr/local/go/bin:"+system.DefaultPathEnvUnix).
 		AddEnv("GOPATH", "/go").
 		Run(llb.Shlex("apk add --no-cache g++ linux-headers")).
 		Run(llb.Shlex("apk add --no-cache git libseccomp-dev make")).Root()
diff --git a/examples/buildkit1/buildkit.go b/examples/buildkit1/buildkit.go
index c6dad534816c..ea3e558e1809 100644
--- a/examples/buildkit1/buildkit.go
+++ b/examples/buildkit1/buildkit.go
@@ -35,7 +35,7 @@ func main() {
 func goBuildBase() llb.State {
 	goAlpine := llb.Image("docker.io/library/golang:1.13-alpine")
 	return goAlpine.
-		AddEnv("PATH", "/usr/local/go/bin:"+system.DefaultPathEnv).
+		AddEnv("PATH", "/usr/local/go/bin:"+system.DefaultPathEnvUnix).
 		AddEnv("GOPATH", "/go").
 		Run(llb.Shlex("apk add --no-cache g++ linux-headers")).
 		Run(llb.Shlex("apk add --no-cache git libseccomp-dev make")).Root()
diff --git a/examples/buildkit2/buildkit.go b/examples/buildkit2/buildkit.go
index 4bd55bef93a1..9e82d3adee0a 100644
--- a/examples/buildkit2/buildkit.go
+++ b/examples/buildkit2/buildkit.go
@@ -35,7 +35,7 @@ func main() {
 func goBuildBase() llb.State {
 	goAlpine := llb.Image("docker.io/library/golang:1.13-alpine")
 	return goAlpine.
-		AddEnv("PATH", "/usr/local/go/bin:"+system.DefaultPathEnv).
+		AddEnv("PATH", "/usr/local/go/bin:"+system.DefaultPathEnvUnix).
 		AddEnv("GOPATH", "/go").
 		Run(llb.Shlex("apk add --no-cache g++ linux-headers libseccomp-dev make")).Root()
 }
diff --git a/examples/buildkit3/buildkit.go b/examples/buildkit3/buildkit.go
index 4ddcf59ef829..633891483d19 100644
--- a/examples/buildkit3/buildkit.go
+++ b/examples/buildkit3/buildkit.go
@@ -36,7 +36,7 @@ func main() {
 func goBuildBase() llb.State {
 	goAlpine := llb.Image("docker.io/library/golang:1.13-alpine")
 	return goAlpine.
-		AddEnv("PATH", "/usr/local/go/bin:"+system.DefaultPathEnv).
+		AddEnv("PATH", "/usr/local/go/bin:"+system.DefaultPathEnvUnix).
 		AddEnv("GOPATH", "/go").
 		Run(llb.Shlex("apk add --no-cache g++ linux-headers libseccomp-dev make")).Root()
 }
diff --git a/examples/nested-llb/main.go b/examples/nested-llb/main.go
index 1c15934091eb..d53aa57cb43f 100644
--- a/examples/nested-llb/main.go
+++ b/examples/nested-llb/main.go
@@ -34,7 +34,7 @@ func main() {
 func goBuildBase() llb.State {
 	goAlpine := llb.Image("docker.io/library/golang:1.13-alpine")
 	return goAlpine.
-		AddEnv("PATH", "/usr/local/go/bin:"+system.DefaultPathEnv).
+		AddEnv("PATH", "/usr/local/go/bin:"+system.DefaultPathEnvUnix).
 		AddEnv("GOPATH", "/go").
 		Run(llb.Shlex("apk add --no-cache g++ linux-headers make")).Root()
 }
diff --git a/exporter/containerimage/writer.go b/exporter/containerimage/writer.go
index a0858801c1b2..bfee4d15801a 100644
--- a/exporter/containerimage/writer.go
+++ b/exporter/containerimage/writer.go
@@ -315,7 +315,7 @@ func emptyImageConfig() ([]byte, error) {
 	}
 	img.RootFS.Type = "layers"
 	img.Config.WorkingDir = "/"
-	img.Config.Env = []string{"PATH=" + system.DefaultPathEnv}
+	img.Config.Env = []string{"PATH=" + system.DefaultPathEnv(pl.OS)}
 	dt, err := json.Marshal(img)
 	return dt, errors.Wrap(err, "failed to create empty image config")
 }
diff --git a/frontend/dockerfile/dockerfile2llb/convert.go b/frontend/dockerfile/dockerfile2llb/convert.go
index ca5d9c5b49bc..213c671eaff1 100644
--- a/frontend/dockerfile/dockerfile2llb/convert.go
+++ b/frontend/dockerfile/dockerfile2llb/convert.go
@@ -317,7 +317,11 @@ func Dockerfile2LLB(ctx context.Context, dt []byte, opt ConvertOpt) (*llb.State,
 
 		// make sure that PATH is always set
 		if _, ok := shell.BuildEnvs(d.image.Config.Env)["PATH"]; !ok {
-			d.image.Config.Env = append(d.image.Config.Env, "PATH="+system.DefaultPathEnv)
+			var os string
+			if d.platform != nil {
+				os = d.platform.OS
+			}
+			d.image.Config.Env = append(d.image.Config.Env, "PATH="+system.DefaultPathEnv(os))
 		}
 
 		// initialize base metadata from image conf
diff --git a/frontend/dockerfile/dockerfile2llb/image.go b/frontend/dockerfile/dockerfile2llb/image.go
index 55e9add23363..6eb4cf6e7ae0 100644
--- a/frontend/dockerfile/dockerfile2llb/image.go
+++ b/frontend/dockerfile/dockerfile2llb/image.go
@@ -74,6 +74,6 @@ func emptyImage(platform specs.Platform) Image {
 	}
 	img.RootFS.Type = "layers"
 	img.Config.WorkingDir = "/"
-	img.Config.Env = []string{"PATH=" + system.DefaultPathEnv}
+	img.Config.Env = []string{"PATH=" + system.DefaultPathEnv(platform.OS)}
 	return img
 }
diff --git a/frontend/gateway/container.go b/frontend/gateway/container.go
index 9981124c40f4..99a3640ddd53 100644
--- a/frontend/gateway/container.go
+++ b/frontend/gateway/container.go
@@ -227,7 +227,7 @@ func (gwCtr *gatewayContainer) Start(ctx context.Context, req client.StartReques
 	if procInfo.Meta.Cwd == "" {
 		procInfo.Meta.Cwd = "/"
 	}
-	procInfo.Meta.Env = addDefaultEnvvar(procInfo.Meta.Env, "PATH", utilsystem.DefaultPathEnv)
+	procInfo.Meta.Env = addDefaultEnvvar(procInfo.Meta.Env, "PATH", utilsystem.DefaultPathEnvUnix) // support windows?
 	if req.Tty {
 		procInfo.Meta.Env = addDefaultEnvvar(procInfo.Meta.Env, "TERM", "xterm")
 	}
diff --git a/solver/llbsolver/ops/exec.go b/solver/llbsolver/ops/exec.go
index e5aeeea12b8f..5516376fd8ae 100644
--- a/solver/llbsolver/ops/exec.go
+++ b/solver/llbsolver/ops/exec.go
@@ -380,7 +380,11 @@ func (e *execOp) Exec(ctx context.Context, g session.Group, inputs []solver.Resu
 	if e.op.Meta.ProxyEnv != nil {
 		meta.Env = append(meta.Env, proxyEnvList(e.op.Meta.ProxyEnv)...)
 	}
-	meta.Env = addDefaultEnvvar(meta.Env, "PATH", utilsystem.DefaultPathEnv)
+	var currentOS string
+	if e.platform != nil {
+		currentOS = e.platform.OS
+	}
+	meta.Env = addDefaultEnvvar(meta.Env, "PATH", utilsystem.DefaultPathEnv(currentOS))
 
 	stdout, stderr := logs.NewLogStreams(ctx, os.Getenv("BUILDKIT_DEBUG_EXEC_OUTPUT") == "1")
 	defer stdout.Close()
diff --git a/util/system/path.go b/util/system/path.go
new file mode 100644
index 000000000000..f6dc70dc8dd5
--- /dev/null
+++ b/util/system/path.go
@@ -0,0 +1,18 @@
+package system
+
+// DefaultPathEnvUnix is unix style list of directories to search for
+// executables. Each directory is separated from the next by a colon
+// ':' character .
+const DefaultPathEnvUnix = "/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin"
+
+// DefaultPathEnvWindows is windows style list of directories to search for
+// executables. Each directory is separated from the next by a colon
+// ';' character .
+const DefaultPathEnvWindows = "c:\\Windows\\System32;c:\\Windows"
+
+func DefaultPathEnv(os string) string {
+	if os == "windows" {
+		return DefaultPathEnvWindows
+	}
+	return DefaultPathEnvUnix
+}
diff --git a/util/system/path_unix.go b/util/system/path_unix.go
index c607c4db09f2..f3762e69d36a 100644
--- a/util/system/path_unix.go
+++ b/util/system/path_unix.go
@@ -2,11 +2,6 @@
 
 package system
 
-// DefaultPathEnv is unix style list of directories to search for
-// executables. Each directory is separated from the next by a colon
-// ':' character .
-const DefaultPathEnv = "/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin"
-
 // CheckSystemDriveAndRemoveDriveLetter verifies that a path, if it includes a drive letter,
 // is the system drive. This is a no-op on Linux.
 func CheckSystemDriveAndRemoveDriveLetter(path string) (string, error) {
diff --git a/util/system/path_windows.go b/util/system/path_windows.go
index cbfe2c1576ce..3fc47449484e 100644
--- a/util/system/path_windows.go
+++ b/util/system/path_windows.go
@@ -8,10 +8,6 @@ import (
 	"strings"
 )
 
-// DefaultPathEnv is deliberately empty on Windows as the default path will be set by
-// the container. Docker has no context of what the default path should be.
-const DefaultPathEnv = ""
-
 // CheckSystemDriveAndRemoveDriveLetter verifies and manipulates a Windows path.
 // This is used, for example, when validating a user provided path in docker cp.
 // If a drive letter is supplied, it must be the system drive. The drive letter