These raw data accompany the article Conley and Lattanzio (2022, Functional Ecology), entitled 'Active regulation of ultraviolet light exposure overrides thermal preference behavior in eastern fence lizards'. ---Contents All data were collected on eastern fence lizards (Sceloporus undulatus) and done either at our field site or within a university research lab. There are seven (7) total tabs in the EXCEL file. Hereafter we list variables in each tab in the order of appearance from left to right. The first tab (field_and_histogram_data) includes data from the field and data for the histograms shown in Figs. 1 and 2: individual id (capture number), sex (male or female), field body temperature (celsius), field UV exposure (UV index [UVI]), pooled UV set-point minimum and maximum for S. undulatus in our dataset (both in UVI), UV exposure minimum and maximum for S. undulatus estimated in a prior study by Ferguson et al. (2010, Zoo Biology) (in UVI), pooled thermal set-point minimum and maximum for S. undulatus in our dataset (both in Celsius). The second tab (UVdata_Treatments2_3) includes UV data from treatments 2 and 3 in our study: individual id (capture number), sex (male or female), treatment (uv = treatment 2, temp_uv = treatment 3), mean UV preference (in UVI), and UV set-point range (in UVI) values. The third tab (Tempdata_Treatments1_3) includes temperature data from treatments 1 and 3 in our study: individual id (capture number), sex (male or female), treatment (temp = treatment 1, temp_uv = treatment 3), mean thermal preference (in Celsius), and thermal set-point range (in Celsius) values. The fourth tab (SA1 - Body Condition Analysis) includes data used to analyze variation in body condition of S. undulatus over time in Supplementary Appendix 1 in our Supporting Information: individual id (capture number), sex (male or female), snout-vent length (SVL, in mm), and weekly S. undulatus mass measurements, starting on the day of capture (=mass1) (all in g). The fifth tab (SA4 - Complementary Analyses) includes data used to analyze difference values in preference and set-point data between treatments including in Supplementary Appendix 4 in our Supporting Information: individual id (capture number), sex (male or female), difference in mean thermal preference (in Celsius), difference in thermal set-point range (in Celsius), difference in mean UV preference (in UVI), and difference in UV set-point range (in UVI). Raw difference values were calculated as a lizard's value in treatment 3 minus their respective value in treatment 1 (for temperature data) or 2 (for UV data). The sixth tab (SF3 - Sensor Calibration Curve) includes data used to calibrate the analog Adafruit UV sensor to the standard sensors produced by Solarmeter 6.5r UV meter, included in Supplementary Figure 3 in our Supporting Information: Solarmeter UVI reading (in UVI), Adafruit UV sensor output (in mV), slope estimate (slope of best-fit linear trendline set to zero intercept), estimated UVI (conversion of Adafruit UV sensor mV into UVI using the slope estimate [=mV * slope estimate]), the raw difference between estimated and actual UVI (in UVI), and the absolute value of the difference between estimated and actual UVI (in UVI). Differences were calculated as Solarmeter UVI reading minus estimated UVI. The seventh tab (Notes) includes two brief notes to clarify to the reader that data used to produce Supplementary Figure 4 and Supplementary Figure 5 in our Supporting Information are the raw data included in the third and second tabs, respectively. ---Format The file is XLSX format, which is typically opened using Microsoft EXCEL. However, these files can also easily be opened using Google Sheets, LibreOffice Calc, or even directly in the statistical software R/RStudio. To analyze the data we recommend using R (or R as implemented via an RStudio interface), as we reference specific packages throughout the data analysis section of Materials and methods, and in our Supporting Information, that we used in this study. All packages are for the R software environment, and free to use/access.