diff --git a/Core/Loaders.cpp b/Core/Loaders.cpp
index 3197a6dff2..1074c83d54 100644
--- a/Core/Loaders.cpp
+++ b/Core/Loaders.cpp
@@ -676,6 +676,7 @@ void DetectZipFileContents(zip_t *z, ZipFileInfo *info) {
 	bool hasIcon0PNG = false;
 	bool hasPRX = false;
 	bool hasPluginIni = false;
+	bool isPS3SaveData = false;  // Same PARAM.SFO + ICON0.PNG layout as a PSP save, but useless to us.
 	s64 totalFileSize = 0;
 	std::vector<ArchiveEntry> archiveEntries;  // In the root or one level down, where a disc image can be.
 
@@ -757,6 +758,10 @@ void DetectZipFileContents(zip_t *z, ZipFileInfo *info) {
 			if (ZipExtractFileToMemory(z, i, &paramSFOContents)) {
 				ParamSFOData sfo;
 				if (sfo.ReadSFO((const u8 *)paramSFOContents.data(), paramSFOContents.size())) {
+					// PSP saves have category MS, PS3 saves SD.
+					if (sfo.GetValueString("CATEGORY") == "SD") {
+						isPS3SaveData = true;
+					}
 					if (sfo.HasKey("TITLE")) {
 						info->gameTitle = sfo.GetValueString("TITLE");
 						info->savedataTitle = sfo.GetValueString("SAVEDATA_TITLE");
@@ -772,6 +777,9 @@ void DetectZipFileContents(zip_t *z, ZipFileInfo *info) {
 					}
 				}
 			}
+		} else if (lowerCaseName == "param.pfd" || endsWith(lowerCaseName, "/param.pfd")) {
+			// The PS3's save data protection file. PSP saves don't have one.
+			isPS3SaveData = true;
 		} else if (endsWith(lowerCaseName, "/icon0.png")) {
 			hasIcon0PNG = true;
 		} else if (endsWith(lowerCaseName, "/plugin.ini") && slashCount >= 1) {
@@ -827,6 +835,9 @@ void DetectZipFileContents(zip_t *z, ZipFileInfo *info) {
 		info->stripChars = stripCharsTexturePack;
 		info->ignoreMetaFiles = true;
 		info->contents = ZipFileContents::TEXTURE_PACK;
+	} else if (isPS3SaveData) {
+		WARN_LOG(Log::Loader, "Zip contains PS3 save data, not PSP");
+		info->contents = ZipFileContents::UNKNOWN;
 	} else if (stripChars == 0 && filesInRoot == 0 && hasParamSFO && hasIcon0PNG && !isExtractedISO) {
 		// As downloaded from GameFAQs, for example.
 		info->contents = ZipFileContents::SAVE_DATA;
diff --git a/unittest/TestZipSlip.cpp b/unittest/TestZipSlip.cpp
index 17994606e0..58fe08dd4d 100644
--- a/unittest/TestZipSlip.cpp
+++ b/unittest/TestZipSlip.cpp
@@ -184,6 +184,53 @@ static bool TestRootSaveDataZip() {
 	return true;
 }
 
+// A PS3 save folder has the same PARAM.SFO + ICON0.PNG layout as a PSP one. Each signal alone must reject it.
+static bool TestPS3SaveDataZip() {
+	Path tempRoot = File::GetCurDirectory() / "unittest_zip_ps3save_test";
+	File::DeleteDirRecursively(tempRoot);
+	EXPECT_TRUE(File::CreateDir(tempRoot));
+
+	for (int variant = 0; variant < 2; variant++) {
+		const bool sdCategory = variant == 0;
+		ParamSFOData sfo;
+		sfo.SetValue("CATEGORY", sdCategory ? "SD" : "MS", 4);
+		sfo.SetValue("TITLE", "Some PS3 game", 128);
+		sfo.SetValue("SAVEDATA_DIRECTORY", "BCES00141", 64);
+		u8 *sfoData = nullptr;
+		size_t sfoSize = 0;
+		sfo.WriteSFO(&sfoData, &sfoSize);
+		std::string sfoContents((const char *)sfoData, sfoSize);
+		delete[] sfoData;
+
+		Path zipPath = tempRoot / "ps3save.zip";
+		int errorp = 0;
+		zip_t *z = zip_open(zipPath.c_str(), ZIP_CREATE | ZIP_TRUNCATE, &errorp);
+		EXPECT_TRUE(z != nullptr);
+		static const char *const contents = "data";
+		zip_source_t *source = zip_source_buffer(z, sfoContents.data(), sfoContents.size(), 0);
+		EXPECT_TRUE(zip_file_add(z, "BCES00141/PARAM.SFO", source, ZIP_FL_ENC_UTF_8) >= 0);
+		std::vector<const char *> names = { "BCES00141/ICON0.PNG", "BCES00141/0" };
+		if (!sdCategory) {
+			names.push_back("BCES00141/PARAM.PFD");
+		}
+		for (const char *name : names) {
+			source = zip_source_buffer(z, contents, strlen(contents), 0);
+			EXPECT_TRUE(zip_file_add(z, name, source, ZIP_FL_ENC_UTF_8) >= 0);
+		}
+		EXPECT_TRUE(zip_close(z) == 0);
+
+		z = zip_open(zipPath.c_str(), 0, &errorp);
+		EXPECT_TRUE(z != nullptr);
+		ZipFileInfo info;
+		DetectZipFileContents(z, &info);
+		zip_close(z);
+		EXPECT_EQ_INT((int)info.contents, (int)ZipFileContents::UNKNOWN);
+	}
+
+	File::DeleteDirRecursively(tempRoot);
+	return true;
+}
+
 static bool TestIsSafePathComponent() {
 	EXPECT_TRUE(IsSafePathComponent("ULUS10041"));
 	EXPECT_TRUE(IsSafePathComponent("NPJH-50465"));
@@ -214,5 +261,7 @@ bool TestZipSlip() {
 		return false;
 	if (!TestRootSaveDataZip())
 		return false;
+	if (!TestPS3SaveDataZip())
+		return false;
 	return true;
 }