diff --git a/cmd/mutagen/project/flush.go b/cmd/mutagen/project/flush.go
index b4ac8e00..606a1a1b 100644
--- a/cmd/mutagen/project/flush.go
+++ b/cmd/mutagen/project/flush.go
@@ -28,7 +28,7 @@ func flushMain(command *cobra.Command, arguments []string) error {
 	// relative paths (including relative synchronization paths and relative
 	// Unix Domain Socket paths) to be resolved relative to the project
 	// configuration file.
-	configurationFileName := project.DefaultConfigurationFileName
+	configurationFileName := project.ConfigurationFileName()
 	if flushConfiguration.projectFile != "" {
 		var directory string
 		directory, configurationFileName = filepath.Split(flushConfiguration.projectFile)
diff --git a/cmd/mutagen/project/list.go b/cmd/mutagen/project/list.go
index 2df690bb..bdfef5f1 100644
--- a/cmd/mutagen/project/list.go
+++ b/cmd/mutagen/project/list.go
@@ -29,7 +29,7 @@ func listMain(command *cobra.Command, arguments []string) error {
 	// relative paths (including relative synchronization paths and relative
 	// Unix Domain Socket paths) to be resolved relative to the project
 	// configuration file.
-	configurationFileName := project.DefaultConfigurationFileName
+	configurationFileName := project.ConfigurationFileName()
 	if listConfiguration.projectFile != "" {
 		var directory string
 		directory, configurationFileName = filepath.Split(listConfiguration.projectFile)
diff --git a/cmd/mutagen/project/pause.go b/cmd/mutagen/project/pause.go
index 291f6f7a..ff3493c2 100644
--- a/cmd/mutagen/project/pause.go
+++ b/cmd/mutagen/project/pause.go
@@ -30,7 +30,7 @@ func pauseMain(command *cobra.Command, arguments []string) error {
 	// relative paths (including relative synchronization paths and relative
 	// Unix Domain Socket paths) to be resolved relative to the project
 	// configuration file.
-	configurationFileName := project.DefaultConfigurationFileName
+	configurationFileName := project.ConfigurationFileName()
 	if pauseConfiguration.projectFile != "" {
 		var directory string
 		directory, configurationFileName = filepath.Split(pauseConfiguration.projectFile)
diff --git a/cmd/mutagen/project/reset.go b/cmd/mutagen/project/reset.go
index e9115223..5b2fc3d9 100644
--- a/cmd/mutagen/project/reset.go
+++ b/cmd/mutagen/project/reset.go
@@ -28,7 +28,7 @@ func resetMain(command *cobra.Command, arguments []string) error {
 	// relative paths (including relative synchronization paths and relative
 	// Unix Domain Socket paths) to be resolved relative to the project
 	// configuration file.
-	configurationFileName := project.DefaultConfigurationFileName
+	configurationFileName := project.ConfigurationFileName()
 	if resetConfiguration.projectFile != "" {
 		var directory string
 		directory, configurationFileName = filepath.Split(resetConfiguration.projectFile)
diff --git a/cmd/mutagen/project/resume.go b/cmd/mutagen/project/resume.go
index 8903c782..c5e4b324 100644
--- a/cmd/mutagen/project/resume.go
+++ b/cmd/mutagen/project/resume.go
@@ -30,7 +30,7 @@ func resumeMain(command *cobra.Command, arguments []string) error {
 	// relative paths (including relative synchronization paths and relative
 	// Unix Domain Socket paths) to be resolved relative to the project
 	// configuration file.
-	configurationFileName := project.DefaultConfigurationFileName
+	configurationFileName := project.ConfigurationFileName();
 	if resumeConfiguration.projectFile != "" {
 		var directory string
 		directory, configurationFileName = filepath.Split(resumeConfiguration.projectFile)
diff --git a/cmd/mutagen/project/run.go b/cmd/mutagen/project/run.go
index a8206d47..8618b6cc 100644
--- a/cmd/mutagen/project/run.go
+++ b/cmd/mutagen/project/run.go
@@ -33,7 +33,7 @@ func runMain(_ *cobra.Command, arguments []string) error {
 	// relative paths (including relative synchronization paths and relative
 	// Unix Domain Socket paths) to be resolved relative to the project
 	// configuration file.
-	configurationFileName := project.DefaultConfigurationFileName
+	configurationFileName := project.ConfigurationFileName()
 	if runConfiguration.projectFile != "" {
 		var directory string
 		directory, configurationFileName = filepath.Split(runConfiguration.projectFile)
diff --git a/cmd/mutagen/project/start.go b/cmd/mutagen/project/start.go
index 3f8b657a..ecd370a2 100644
--- a/cmd/mutagen/project/start.go
+++ b/cmd/mutagen/project/start.go
@@ -39,7 +39,7 @@ func startMain(command *cobra.Command, arguments []string) error {
 	// relative paths (including relative synchronization paths and relative
 	// Unix Domain Socket paths) to be resolved relative to the project
 	// configuration file.
-	configurationFileName := project.DefaultConfigurationFileName
+	configurationFileName := project.ConfigurationFileName()
 	if startConfiguration.projectFile != "" {
 		var directory string
 		directory, configurationFileName = filepath.Split(startConfiguration.projectFile)
diff --git a/cmd/mutagen/project/terminate.go b/cmd/mutagen/project/terminate.go
index d099a1b6..7e3abb35 100644
--- a/cmd/mutagen/project/terminate.go
+++ b/cmd/mutagen/project/terminate.go
@@ -30,7 +30,7 @@ func terminateMain(command *cobra.Command, arguments []string) error {
 	// relative paths (including relative synchronization paths and relative
 	// Unix Domain Socket paths) to be resolved relative to the project
 	// configuration file.
-	configurationFileName := project.DefaultConfigurationFileName
+	configurationFileName := project.ConfigurationFileName()
 	if terminateConfiguration.projectFile != "" {
 		var directory string
 		directory, configurationFileName = filepath.Split(terminateConfiguration.projectFile)
diff --git a/pkg/project/paths.go b/pkg/project/paths.go
index 35672084..bde143f2 100644
--- a/pkg/project/paths.go
+++ b/pkg/project/paths.go
@@ -1,5 +1,7 @@
 package project
 
+import "os"
+
 const (
 	// DefaultConfigurationFileName is the name of the Mutagen project
 	// configuration file.
@@ -8,3 +10,11 @@ const (
 	// order to compute the corresponding lock file.
 	LockFileExtension = ".lock"
 )
+
+func ConfigurationFileName() string {
+  fileName := os.Getenv("MUTAGEN_PROJECT_FILE")
+  if fileName == "" {
+    return DefaultConfigurationFileName
+  }
+  return fileName
+}