Operator
Ladies and gentlemen, thank you for standing by, and welcome to the Trimble Fourth Quarter and 2020 Results Conference Call. [Operator Instructions]
Now I would like to turn it over to Mr. Rob Painter, Chief Executive Officer of Trimble.
Robert Painter --
President and Chief Executive Officer
Hello, everyone. Before I get started, a quick reminder that our presentation is available on our website, and we ask that you please refer to the safe harbor at the back. In addition, please note that we will be comparing against the 2019 that had a 14th week in the fourth quarter. Let's start on slide two with the three key messages we want to convey today. First, the customer ROI of our technology and the strength of our financial model enabled us to outperform our own expectations in the fourth quarter. Our customer value proposition is rooted in productivity, quality, safety, visibility and sustainability. We are pleased to announce that annualized recurring revenue, or ARR, grew 9% year-over-year to $1.3 billion, while quarterly revenue grew 0.4% year-over-year to $830 million. Expanding gross margins and execution on costs led to adjusted EBITDA margin of 26.1%, and we finished the year delivering a record $672 million of operating cash flow. Second, executing the Connect & Scale 2025 strategy remains our focus. We are working to connect stakeholders across industry life cycles and to transform customer workflows while simultaneously making ourselves easier to do business with. As leaders of the business, we take our responsibility seriously to be effective allocators of capital. To this end, we will continue to invest disproportionately in our cloud and autonomy capabilities as well as in go-to-market efforts to support and enable our long-term growth opportunities. Third, our long-term market conviction remains strong. We believe the secular trends of digitization provide long-term tailwinds, and we maintain our result to exit this crisis on a stronger competitive footing than we entered it. As we come into 2021, we are both cautious and humble to recognize market uncertainty and volatility while also confident that we are on the right track. Comparisons against 2020, especially on a quarterly basis, will be difficult, if not irrelevant.