Recent studies have examined patterns of use of lexical bundles and provided beneficial information about their different structures and functions in written and spoken registers. Some of the previous studies compared the differences of L1 versus L2 English writers in the usage of lexical bundles in English written texts while some other studies focused on the patterns of lexical bundles utilized by novice or expert writers. However, there were not so many studies which analyzed engagement bundles (EBs) cross-culturally in physics research articles. To fill this gap, the present study analyzed 163 L1-English, L2-English, and L1-Persian articles and compared the results in order to perceive the differences as well as similarities among native and non-native writers. The AntConc 3.5.0 software was utilized as the main instrument in the present study. The structure of identified EBs were classified based on the structural taxonomy proposed by Biber, Johanson, Leech, Conrad and Finegan (1999). The functional elements proposed by Hyland(2005b) were identified to determine engagement markers.Using AntConc software, there were 23 and 56 four-word EBs identified in L1-EC and L2-EC, respectively. Also, there were 52 EBs identified in L1-PC manually to compare the structures and functions of these bundles utilized by L1-Persian writers when they produce English or Persian texts in physics discipline. The results of the study indicated that there were structural and functional differences in the usage of EBs, in terms of frequency, between L1-English versus L2-English writers and L1-English versus L1-Presian writers, but there were not significant differences between L2-English versus L1-Persian writers. However, there were not major structural (clausal versus phrasal) and functional (directives, reader pronouns or shared knowledge elements) differences between the three groups of writers. In other words, L1-English, L2-English and L1-Persian writers favored the usage of clausal and more directive EBs through their physics research articles. The relationship between the structural and functional categories demonstrated that most of the structures utilized for EBs serve the same function of directing the readers through the text. In addition, it was indicated that L2-English writers (who have L1-Persian) tend to use EBs which have structures and functions more similar to those utilized in Persian texts than native-like bundles. Key words: academic writing, culture, engagement markers, function, lexical bundles, metadiscourse