diff --git a/lib/createInlinePluginCreator.js b/lib/createInlinePluginCreator.js
index 3fb950f..f7c89b3 100644
--- a/lib/createInlinePluginCreator.js
+++ b/lib/createInlinePluginCreator.js
@@ -126,7 +126,8 @@ function createInlinePluginCreator(packages, multiContext) {
 		 */
 		const analyzeCommits = async (pluginOptions, context) => {
 			// Filter commits by directory.
-			commits = await getCommitsFiltered(cwd, dir, context.lastRelease.gitHead);
+			commits = await getCommitsFiltered(cwd, dir, context.lastRelease.gitHead, context.branch.name);
+			// context.logger.log("filtered commits", JSON.stringify(commits, null, 2));
 
 			// Set context.commits so analyzeCommits does correct analysis.
 			context.commits = commits;
diff --git a/lib/getCommitsFiltered.js b/lib/getCommitsFiltered.js
index cd7579a..1ed61be 100644
--- a/lib/getCommitsFiltered.js
+++ b/lib/getCommitsFiltered.js
@@ -14,9 +14,10 @@ const cleanPath = require("./cleanPath");
  * @param {string} cwd Absolute path of the working directory the Git repo is in.
  * @param {string} dir Path to the target directory to filter by. Either absolute, or relative to cwd param.
  * @param {string|void} lastHead The SHA of the previous release
+ * @param {string|void} branch first-parent to determine which merges went into master
  * @return {Promise<Array<Commit>>} The list of commits on the branch `branch` since the last release.
  */
-async function getCommitsFiltered(cwd, dir, lastHead = undefined) {
+async function getCommitsFiltered(cwd, dir, lastHead = undefined, branch = "master") {
 	// Clean paths and make sure directories exist.
 	check(cwd, "cwd: directory");
 	check(dir, "dir: path");
@@ -43,7 +44,7 @@ async function getCommitsFiltered(cwd, dir, lastHead = undefined) {
 	// Use git-log-parser to get the commits.
 	const relpath = relative(root, dir);
 	const stream = gitLogParser.parse(
-		{ _: [lastHead ? `${lastHead}..HEAD` : "HEAD", "--", relpath] },
+		{ _: ["--first-parent", branch, lastHead ? `${lastHead}..HEAD` : "HEAD", "--", relpath] },
 		{ cwd, env: process.env }
 	);
 	const commits = await getStream.array(stream);